CHEMISTRY PRACTICAL NOTEBOOK STANDARD XI (agm`Zemó àmË`{jH$ Zm|Xdhr B`Îmm 11 dr) < 59.00 CHEMISTRY Standard XI Practical Notebook Name of the students : Name of the Junior college: Class : Division : Roll No. : Audio - Visual study material about practicals can be obtained through DIKSHA APP on your smartphone by using Q.R.Code. Maharashtra State Bureau of Textbook Production and Curriculum Research, Pune - 411 004. A First Edition : 2019 © Maharashtra State Bureau of Textbook Production and Curriculum Research, Pune 411 004. The Maharashtra State Bureau of Textbook Production and Curriculum Research reserves all rights relating to the practical Notebook. No part of this book should be reproduced without the written permission of the Director. Maharashtra State Bureau of Textbook Production and Curriculum Research. 'Balbharati', Senapati Bapat Marg, Pune - 411004. Subject Committee: Dr. Chandrashekhar V. Murumkar, Chairman Dr. Sushama Dilip Joag, Member Dr. Shridhar Pandurang Gejji, Member Dr. Satyawati Sudhir Joshi, Member Dr. Rajashree Vikas Kashalkar, Member Dr. Laxman Shamrao Patil, Member Shri. Rajesh Vamanrao Roman Shri. Rajiv Arun Patole, Member Secretary Cover and illustration : Shri. Vivekanand Patil Shri. Shubham Chavan Typesetting DTP Section, Textbook Bureau, Pune Co-ordination : Shri. Rajiv Arun Patole Special Officer for Chemistry Study group : Dr. Anjali Deepak Ruikar Shri. Sachin Ashok Bartakke Smt. Archana Sanjeev Kale Smt. Pushpalata Babanrao Gangarde Smt. Archana Dipak Harimkar Shri. Vishnu Rustumrao Deshmukh Shri. Sharad Ajabrao Mankar Shri. Ritesh Vijay Bijewar Shri. Rupesh Dinkar Thakur Shri. Milind Chandrakant Gaikwad Shri. Gajanan Shivajirao Suryawanshi Paper : 70 GSM Creamwove Print Order : Printer Production : Shri. Sachchitanand Aphale Chief Production Officer Shri. Liladhar Atram Production Officer Smt. Prachi Ravindra Sathe Chief Co-ordinator Publisher : Shri. Vivek Uttam Gosavi Controller Maharashtra State Textbook Bureau Prabhadevi, Mumbai-400 025. DISCLAIMER Note: All attempts have been made to contact copy righters © but we have not heard from them. We will pleased to acknowledge the copy right holder (s) in our next edition if we learn from them. B Foreward Dear Friends, The National Curriculum Framework (NCF) 2005 and State Curriculum Frame (SCF) 2010, recommend that children′s life at school must be linked to their daily life. That is why a new educational system linking school, society and family is forming to replace bookish education. While the boundaries of different subjects are becoming gray, it has become very much necessary to develop subject related skills and understanding of the fundamental concepts, and to cultivate taste for the concerned subject and to nurture analytical and application oriented abilities among the students. Chemistry is a subject that must be learnt through experiments and observations. Laboratory is a place where students have opportunities for clarification of concepts of all branches of chemistry, e.g. physical chemistry, organic chemistry, analytical chemistry, etc. Laboratory work includes qualitative analysis experiments like radical detection, analytical techniques such as filtration, distilation, and quantitative analysis. While performing experiments in quatitative analysis like titration, students have to estimate the errors in their readings and observations. These aspects have been covered in the notebook along with supplimentary information and illustrations, which will facilitate teachers in the proper evaluation of the students′ work in the laboratory. An opportunity to verify the theoretical part in the textbook is obtained through the experimental work. All these points are taken into account in this notebook. It will be possible to evaluate the students, with respect to acquired basic experimental skills in chemistry, observational methods and accuracy, and calculation abilities. A detailed procedure is given for the experiments and also activities included in the theory textbook as per the syllabus. In addition, thought provoking questions based on the practicals are included. All these should be used not only for the practical examination, but a broader expectation is that these would be useful for science education through experimental skill. This notebook could be used as a good supplimentary material for learning chemistry. QR code is given on first page; by using QR code you can get additional audio-visual information regarding experiments and activities. We are sure, you all will welcome this chemistry practical notebook prepared with due concern and care. Also we take this opportunity to wish you all the best for your educational career. (Dr. Sunil Magar) Director Pune Date : 20 June 2019 Bharatiya Saur: 30 Jyeshtha 1941 Maharashtra State Bureau of Textbook Production and Curriculum Research, Pune 411 004. C General Instructions Safety guidelines in chemistry laboratory Do’s 1) 2) 3) 4) 5) 6) 7) 8) 9) Read the chemical safety information carefully. Always wear apron or laboratory coat. Identify the safety equipments. Use safety goggles whenever necessary. Handle corrosive chemicals carefully like acids. Tie long hair back. Always wash your hands with soap before leaving the laboratory. In case of any accident, notify the instructor immediately. Avoid direct contact with chemicals. If chemicals come in contact with your skin or eyes, flush immediately with copious amount of water and consult with your instructor. 10) Close gas tab before leaving laboratory (if used) 1) 2) 3) 4) 5) Don’ts Do not pipette out the solution with mouth. Use of pro-pipette bulb is recommended. Don’t casually dispose of chemicals down the drain. Don’t eat or drink in the laboratory. Don’t play mad scientist. Don’t haphazardly mix chemicals. Important: Avoid casual approach towards safety. Evaluation Scheme of Practical examination in chemistry First Terminal Practical Examination Time 2 hours A B C Std- XI Science Marks 20 Any one long experiment (1 hour 30 min) Passing Mark 07 10 marks i) Conduction of experiment 03 marks ii) Observations 04 marks iii) Calculation 02 marks iv) Result with proper unit 01 mark Any one activity (30 min) 05 marks i) Conduction of activity 01 marks ii) Observation 03 marks iii) Conclusion/Result 01 mark Viva / oral based upon experiment / activity performed during examination 05 marks (Viva / oral should be taken while experiments / activities are being performed) D Handbook and Journal of Experiment in Subject CHEMISTRY for Std. XI Annual Practical Examination Time 3 hours A Std – XI Science Total marks 30 One long experiment Quantitative analysis 1 hour 30 min Passing Marks 11 10 marks i) Conduction of experiment 03 marks ii) Observations 04 marks iii) Calculation 02 marks iv) Result with proper unit 01 mark OR B C D long experiment: Qualitative analysis 1 hour 30 min i) Preliminary Tests 01 mark ii) Dry tests of basic radical and acidic radical 02 marks iii) Detection of group of basic radical 01 mark iv) Detection of basic radical and confirmatory test 02 marks v) Detection of acidic radical and confirmatory test 02 marks vi) Result (Basic radical and acidic radical with proper oxidation state, correct molecular formula and name of the salt) 02 marks One short experiment 45 min 05 marks i) Conduction of experiment 01 marks ii) Observations 03 marks iii) Calculation / Conclusion / Result 01 mark Any one activity 35 min 05 marks i) Conduction of activity 01 marks ii) Observation 03 marks iii) Result / conclusion 01 mark E Viva based on experiments / activity performed during examination F Certified laboratory Journal 10 min 05 marks 05 marks Note: Minimum 15 experiments and 5 activities should be performed during the year. 1 Index Sr. No. Page No. Experiments Date Remark Signature Introduction to Chemistry laboratory 1 Introduction to apparatus used in chemistry laboratory. Basic Chemistry laboratory techniques 2 Study of burner, operating pinch cock / stopcock and handling of concentrated acid containers. Quantitative Analysis (Long Experiments) (Compulsory) 3 To determine concentration in terms of molarity of NaOH by titrating it against (0.05M) standard solution of oxalic acid. 4 To determine concentration in terms of molarity of HCl by titrating it against (0.05M) standard solution of sodium carbonate. Qualitative Analysis (Long Experiment) (Any four water soluble salt) Detection of one basic radical (cation) and one acidic radical (anion) qualitatively from given inorganic salt. 5 The given inorganic salt no. 1 contains 1) Basic radical.........2) Acidic radical........ 3) Formula of the salt.................................. 6 The given inorganic salt no. 2 contains 1) Basic radical.........2) Acidic radical........ 3) Formula of the salt.................................. 7 The given inorganic salt no. 3 contains 1) Basic radical.........2) Acidic radical........ 3) Formula of the salt.................................. 8 The given inorganic salt no. 4 contains 1) Basic radical.........2) Acidic radical........ 3) Formula of the salt.................................. 9 The given inorganic salt no. 5 contains 1) Basic radical.........2) Acidic radical........ 3) Formula of the salt.................................. Surface Chemistry (Short Experiments) (Any Two) 10 To prepare colloidal solution of starch. 11 To prepare colloidal solution of ferric hydroxide [Fe(OH)3] 12 Study of role of emulsifying agent in stabilizing the emulsion of an oil. 2 Sr. No. Page No. Experiments Date Remark Signature Chemical Equilibrium (Short Experiments) (Any One) 13 Study the shift in equilibrium position between ferric ions and thiocyanate ions by increasing the concentration of either of the ions. 14 Study the shift in equilibrium position between [Co(H2O)6]2+ ions and chloride ions by increasing the concentration of either of the ions. Experiment based on pH change (Short Experiments) (Any One) 15 Study of the pH change in the titration of strong base (0.1 M NaOH) and strong acid (0.1 M HCl) using universal indicator. 16 Determination of the pH and nature of solution of some salts using pH paper or universal indicator. (NH4Cl, Na2CO3 , CH3COONa, NaCl, unknown salt) Characterization and purification of chemical substances 17 Determination of melting point of given organic solid. 18 Determination of boiling point of given organic liquid. 19 Crystallisation of an impure sample of copper sulfate or benzoic acid. List of Activities 1 Prepartion of 100 mL of 0.1 M standard oxalic acid solution. 2 Determination of pH of different fruit juices by using pH paper or universal indicator. 3 Calibration of pipette by burette. 4 To obtain pure water from impure water containing ink by simple distillation method . 5 Checking the adulteration in given food materials. 6 To determine pH of HCl solution of various concentrations by using pH paper or universal indicator. 7 To determine pH of NaOH solution of various concentrations by using pH paper or universal indicator. 3 Date: / / Experiment No. 1 Introduction to apparatus used in Chemistry laboratory In chemistry laboratory students use different apparatus in various experiments. So at first, students should know the name of each apparatus and its use (Fig. 1.1). --------------------------------------------------------------- ------------------------------ --------------- --------------- ------------------------------------------- ----------------------------- --------------- -------------- ----------------------------- --------------- ------------------------------------------- ----------------------------- ----------------------------- -------------- ---------------------------- --------------------------------------------------------- --------------------------------------------------------- -------------- Fig. 1.1 Chemistry Laboratory apparatus 4 ----------------------------- The most common apparatus used to measure the volume of a solution are : 1. Measuring cylinder 2. Volumetric fl ask 3. Pipette 4. Burette Measuring cylinders: These are vertical cylindrical glass vessels of different capacities such as 5 mL, 10 mL, 25 mL, 50 mL, 100 mL, 250 mL, 1000 mL, etc. (Fig. 1.2). Measuring cylinders are used to measure the volume of solution. Fig. 1.2 Measuring cylinder (100 mL) Volumetric flasks: These are glass vessels with a fl at bottom and a long neck on which a mark is etched to show the level to which it is to be filled with a solution. Volumetric fl asks of different capacities such as 50 mL, 100 mL, 250 mL, 500 mL, 1000 mL, etc. (Fig. 1.3).Volumetric fl asks are used to prepare standard solution of known concentration. Fig. 1.3 Volumetric flask (100 mL) Pipette: It is used for measuring a small definite volume of a solution. It consists of narrow glass tube blown into a bulb in the middle (Fig.1.4 a and b). At the lower end it is drawn into a jet or nozzle. A circular mark is etched round the pipette to show the level to which it must be filled so as to contain the volume stated on its bulb. Rinsing of pipette: Wash the pipette atleast twice with water and clean it thoroughly before use. Pipette out a little amount of the solution. Hold the pipette horizontally in your hands and rotate it slowly so that all of its inner surface is washed with the solution. This process of washing the pipette with the solution is known as ‘rinsing’. Rinse the pipette atleast twice. The solution used for rinsing is thrown into the sink. The pipette is thus ready to use. 5 How to use pipette: Now suck fresh volume of the solution into the pipette till the level of the solution is sufficiently above the mark. At this stage put your dry index finger at once over the top of the pipette. Gently release the pressure of your index finger, and allow the solution to fl ow down slowly till its level reaches to etched mark. Arrest the fl ow of the solution by increasing the pressure of your finger. Hold the pipette vertical and see that the graduation mark is brought in line with your eye level. The lower meniscus of the solution must be in the line (tangential) with 10 mL 200C Fig. 1.4 (b) Graduated pipette 10 mL Fig 1.4 (a) Pipette 10 mL the etched mark on the pipette. Touch the lower end of the pipette to a clean glass to remove any adhering drop and then introduce it into the titration fl ask. Remove your index finger. The solution runs down the pipette into the fl ask leaving a drop of it in the jet or the nozzle. Never blow out this drop as a pipette is always calibrated to measure the specified volume even when a drop remains in the nozzle. Fig 1.5 (a) Burette with stopcock 25 mL Fig. 1.5 (b) Burette with pinch cock (50 mL) 6 The burette: It is a long glass tube of uniform bore with a stopcock at the bottom. It is used to deliver a solution for titration. The fl ow of the solution for titration can be regulated or stopped as desired by means of the stopcock [Fig. 1.5(a)] Sometimes a rubber tube with a pinch cock is attached to the burette instead of the stopcock [Fig. 1.5 (b)]. How to use burette: The burette is commonly designed to hold 25 mL, 50 mL or 100 mL of the solution and is graduated in tenths of a mL. The zero mark is always at the top and the final mark (25, 50 or 100 mL) at the bottom of the burette. Wash the burette atleast twice with water before use. Then rinse it with the solution (as does in the case of the pipette). Fill it with the solution sufficiently above the zero mark. Turn the stopcock or press the pinch cock to allow the solution to run down and fill the nozzle completely. See that no air bubble is left either in the nozzle or burette. Adjust the level of the solution at the zero mark. The lower meniscus of the solution must be in line with your eye level and the zero mark. Always take solution upto the zero mark as the starting point for every titration. (Although it is not necessary to adjust the burette each time to a zero mark this process avoids the subtraction of two volumes and hence the possibility of an error.) Simple method of getting a correct burette reading is to hold a plain white paper behind the burette. Keep your eye level parallel with the lower meniscus. It is obvious that such a reading is correct (Fig 1.6, b) while those taken from positions ( a and c) other than this, are incorrect (Fig.1.6 a). Correct eye level for reading Fig 1.6 (a) Incorrect burette reading Fig. 1.6 (b) Correct burette reading MCQ Select [3] or underline the most appropriate answer from the given alternatives of each sub question. 1. Glass vessel with a fl at bottom and a long neck on which a mark is etched to show the level is called ................ a. fl at bottom fl ask b. volumetric fl ask c. conical fl ask d. beaker 2. Least count in 100 mL measuring cylinder is ................ a. 10 mL b) 2 mL c) 1 mL d) 0.1 mL 3. The correct burette reading in following diagram is ................ a. 19.5 mL b. 19.6 mL c. 19.7 mL 7 d. 19.8 mL 4. What can you do, when last drop of the solution remain in the jet / nozzle of the pipette? a. Must blow out this drop b. Never blow out this drop c. Equal amount of solution is added to solution d. Remove the drop of solution at any cost. 5. During the observation of burette reading, eye level and solution level in the burette must be in a. same level b. slightly upside level c. slightly below the level d. middle level Short answer questions 1. Why it is necessary to rinse the pipette after washing with water? Ans..................................................................................................................................................... ............................................................................................................................................................ ............................................................................................................................................................ 2. What will happen if we do not remove the air bubble from nozzle of burette? Ans..................................................................................................................................................... ............................................................................................................................................................ ............................................................................................................................................................ 3. What is the simple method of getting a correct reading of burette? Ans..................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ............................................................................................................................................................ 4. Why it is necessary to rinse the burette after washing with water? Ans..................................................................................................................................................... .......................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ 5. Always take the zero mark of lower meniscus as the starting point for every titration. Give reason. Ans..................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ 6. Observe the chemistry laboratory apparatus on page no 4. (Fig 1.1) write their names in space provided. Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 8 NOTES /CALCULATIONS /ROUGH WORK ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ 9 Date: / / Experiment No. 2 Basic Chemistry Laboratory Techniques A) Study of burner The fl ame with which wax or oil burns is luminous, i.e. light emitting. Luminous fl ame introduces soot that acts as a reducing agent, hence the fl ame is a reducing fl ame (yellow in color). This fl ame is rarely used (only for charcoal test) in chemistry laboratory as it does not provide much heat. In the year 1855, a German scientist Bunsen designed a burner that is in use even today. This burner is known as Bunsen burner. It consists of a metal tube with a bore at the base. This bore is surrounded by a metal collar using which, the bore can be opened or closed (Fig. 2.1). Outer zone Inner zone Colorless fl ame Upper oxidising zone Burner tube Hotest portion of fl ame Upper reducing zone Stopcock Collar Middle blue zone Gas tube Lower reducing zone Fig 2.1 Bunsen burner Fig 2.2 Different zones of blue flame There is a nozzle fitted at the base of the burner. When a jet of fuel gas comes out from the nozzle with the bore open, air rushes into the tube and a mixture of fuel and air burns at the end of the metal tube with a blue fl ame. When the gas burns at the end of metal tube with the bore at base closed, combustion takes place in restricted supply of air, resulting in yellow or luminous fl ame. The Fig. 2.2 shows different zones of blue fl ame with which gas burns in Bunsen burner with the bore open. Outer zone of the fl ame is the hottest zone while inner zone is coldest zone. B) Operating pinch cock / stopcock Previously burettes manufactured contained a glass tube calibrated to read volume of solution in mL, which was fitted to a glass nozzle at the bottom with a rubber tube. The rubber tube is closed by a pinch cock. By pressing pinch cock with hand, solution from burette can be added dropwise. However now a days a burette with tefl on stopcock is used instead of a rubber tube with pinch cock. (Fig 2.3) 10 Burette Bure e clamp Bure e stand Stopcock Erienmeyer flask White porcelain le Fig. 2.4 Titration setup Fig. 2.3 Operating stopcock C) Handling of concentrated acid containers Concentrated acids are always kept in glass bottles which are placed in a vessel containing dry sand. These acids are extremely corrosive to all body tissues, especially eyes and skin. These acids are highly toxic. However, if handled safely with the right equipment, acids need not be feared. Use acids confidently by learning how to protect yourself, how to use the proper lab equipment, what to do in the event of spills and other emergencies and how to dispose used acid. At first, when you have to take concentrated acid in a test tube, always use test tube holder. Don’t pipette out concentrated acid by mouth using pipette. If suppose small amount of acid fall on your skin, don’t wash immediately with water. First remove that amount of acid by filter paper, napkin or any other cloth. Then wash your, skin by large amount of water. When you do such a way there will be little amount of hurt to the skin. If your skin gets injured by concentrated acid, after washing your skin, do the dressing to the skin by using antiinfl ammatory cream. After use of concentrated acid, keep the tap of basin on and allow water to fl ush. In this fl ushing water, pour slowly the used acid in the sink. This is called disposal of acid. Do not throw concentrated acid directly in basin. Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 11 MCQ Select [3] or underline the most appropriate answer from given alternatives of each sub question. 1. The fl ame with which wax or oil burns is called a. luminous fl ame c. oxidizing fl ame b. non reducing fl ame d. blue fl ame 2. The figure of Bunsen burner fl ame shows different zones of blue fl ame, which zone of the fl ame is the hottest zone? a. Inner zone c. Outer zone b. Lower zone d. Middle zone 3. If acid comes in contact with your skin, then ----- . a. fl ush immediately with water b. consult with your instructor c. take help with laboratory assistant d. first remove amount of acid with cloth and then fl ush with water. 4. Incorrect statement about easy handling of concentrated acids is ----- . a. storing the acid in glass containers b. using a test tube holder while adding it in a test tube c. using a glass tube with a dropper while adding it in a test tube d. by pipette out with mouth Short answer questions 1. Write the name of flame used in charcoal cavity test. Why? Ans 2. Now a days which type of burette is used instead of rubber tube with pinch cock? Ans 3. Name the apparatus when you have to take concentrated acid in a test tube? Ans 4. How would you dispose concentrated acid in sink after use? Ans 12 5. What is the another name to non-sooty (blue) flame? Ans 6. Label the given diagram of Bunsen burner with the phrases given below. 1. Burner tube 2. Collar 3. Outer zone 4. Inner zone 5. Gas tube 6. Heat proof surface 7. Gas valve 8. Base of burner 9. Air hole Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 13 Quantitative Analysis (Volumetric Analysis) Introduction: A process of quantitative analysis which involves measurement of volume of solution of reacting substance is called as volumetric analysis. The substance or substances to be estimated are in the form of solution. In this process one solution is subjected to react with another solution of known concentration (standard solution) till the reaction is complete. Thus, a volumetric analysis involves a titration between two solutions. The amount of a substance in the given solutions can be calculated from the volume of standard solution used. Some Important Terms Used In Volumetric Analysis: 1. Standard solution: It is a solution which contains a known concentration of an element or a substance.The solution whose concentration is accurately known is called a standard solution. The concentration of the solution used in volumetric analysis is expressed in terms of molarity. 2. Molarity (M): It represents the number of moles of solute per litre of the solution. The solution which contains one gram molecular weight or one mol of the solute in one litre of its solution, is called a molar solution. ? Molarity = Numbers of gram moles of solute Volume of solution in litre Mass of solute in gram = Molar mass × Volume of solution in litre ? 1M solution means 1 mol of solute per litre of solution. 3. Strength: Amount of the substance in grams dissolved per litre of solution. ? Strength of the solution = Molarity × Molar mass of solute 4. Molar mass: It is an algebraic sum of atomic weights of all the atoms present in a molecule. 5. Titration: The process of carrying out a volumetric analysis by using a suitable standard solution ,volumetric apparatus and indicator is called titration. OR It is the process involvming a chemical reaction between a standard solution and the other solution whose concentration is to be determined. Type of Titration: Depending upon nature of reacting species titration methods are generally classified as followsi. Acidimetric and alkalimetry. ii. Oxidation-Reduction titration (Redox titration) iii. Iodometric titration iv. Precipitation titration 6. Titrant: The term referred to the solution filled in the burette. 7. Titrand: The term referred to the solution taken in the conical fl ask . 14 8. End Point: It is the point when the reaction between the two solutions in a titration has just been completed. The end point is indicated by a change in color of the reaction mixture during the reaction. 9. Equivalence Point: It is the point when the reaction between two solutions has been completed just before color change. 10. Indicator: A substance used in titration to indicate the completion of a reaction (that is end point) by its change in color is known as an indicator. The choice of indicator depends upon the nature of acid, base or the substance involved in the titration. Choice of Indicator in Acid Base Titration Sr. No. 1 Acid Strong acid Base Strong base Indicator Color in acid solution Color in basic solution i. Phenolphthalein Colorless Pink ii. Methyl orange Pink Yellow iii. Methyl red Red Yellow 2 Strong acid Weak base Methyl orange Pink Yellow 3 Weak acid Strong base Phenolphthalein Colorless Pink 15 Date: / / Experiment No. 3 Aim: To determine the molarity of the given solution of sodium hydroxide (NaOH) by titrating it against standard solution of (0.05M) oxalic acid. (H2C2O4.2H2O). Apparatus: Burette, pipette, conical fl ask, burette stand, white porcelain tile, etc. Chemicals: Standard solution of (0.05 M) oxalic acid, NaOH solution, phenolphthalein indicator. Principle: This is an alkalimetry type of titration. The titration is in between weak acid (H2C2O4.2H2O) and strong base (NaOH). Procedure: 1. Wash the burette, pipette and conical fl ask with water. 2. Rinse the burette with given NaOH solution and then fill the burette with NaOH solution Remove the air bubble from the nozzle and avoid leakage if any. 3. Adjust the level of the solution up to zero mark and fix it on a burette stand. 4. Rinse the pipette with standard oxalic acid solution. 5. Pipette out 10 mL of 0.05M oxalic acid solution and put it carefully in a clean, empty conical fl ask. Then add 2 drops of phenolphthalein indicator. (The solution remains colorless.) 6. Place the conical fl ask on a white porcelain tile below the burette. 7. Start adding NaOH solution dropwise from the burette in conical fl ask with continuous stirring, till light / faint pink color is obtained in conical fl ask. Stop adding NaOH, this is the end point of titration. 8. Keep the fl ask constantly shaking in a circular manner, this is called swirling of solution. 9. See that the color does not disappear even on vigorous shaking. This is the end point of titration. 10. Note this reading as ‘Pilot’ reading.(Pilot reading is always in whole numbers.) 11. Now fill the burette again with NaOH solution up to the zero mark. 12. Repeat the above procedure and take minimum three more correct burette readings. 13. Note down the constant burette reading .............. ‘x’ mL (C.B.R.) 14. From C.B.R. calculate the molarity of NaOH solution. Observation: 1. Solution in a burette 2. Solution by a pipette 3. Indicator 4. End point 5. Chemical Equation Burette reading Final Initial Difference : : : : : H2C2O4 + 2NaOH Na2C2O4 + 2H2O Observation Table: Pilot reading to mL Burette reading in mL I II III 0.0 0.0 0.0 16 C.B.R. (x) mL Calculations: From above chemical equation 2 mol of NaOH combines with 1 mol of H2C2O4.2H2O ? 80 g NaOH = 126 g H2C2O4.2H2O (Molar mass of NaOH = 40 g mol-1, Molar mass of H2C2O4.2H2O = 126 g mol-1) 1. To calculate ‘g’ of NaOH ? 1000 mL 1M H2C2O4 { 80 g NaOH ? 10 mL 1M H2C2O4 { 0.8 g NaOH ? 10 mL 0.05M H2C2O4 { 0.04 g NaOH Therefore, 0.04 g NaOH is present in .......... (x) mL of NaOH solution of unknown molarity. ? ......... (x) mL NaOH solution contains 0.04 g NaOH ? 1000 mL NaOH solution contains = 1000 × 0.04 ........(x) Space for calculation 2. To calculate molarity of NaOH ?Molarity of NaOH = = g of NaOH 1000 × 0.04 ........(x) × 40 1 ........(x) Result: Solution Molarity NaOH .................. M Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 17 MCQ Select [3] or underline the most appropriate answer from given alternatives of each sub question. 1. A chemical substance indicates completion of the reacting solution by sharp change in its color is called a. catalyst b. an indicator c. an inhibitor d. reagent 2. Sodium oxalate is salt of ...... a. strong acid and weak base b. weak acid and weak base c. weak acid and strong base d. strong acid and strong base 3. In the volumetric analysis of NaOH against 0.05M H2C2O4.2H2O constant burette reading was found to be 9.8 mL. The molarity of NaOH is .......... a. 0.1020 M b. 0.1120 M c. 0.01200 M d. 0.0980 M 4. Indicator used in the titration of weak acid and strong base is .......... a. methyl orange b. phenolphthalein c. litmus d. universal indicator 5. When certain volume of one solution completely reacts with the other solution, this stage of titration is called .......... a. equivalence point b. constant burette reading c. end point d. initial burette reading Short answer questions 1. Why molarity is a temperature dependent quantity? Ans 2. During acid base titration by using phenolphthalein as an indicator, why the color of the reaction mixture changes from colorless to faint pink? Ans 3. Calculate the molar mass of the following compounds? b. Na2CO3 (Atomic mass: C=12, H=1, O=16, S=32 and Na=23) a. H2SO4 Ans a. b. . 4. Define a) molarity b) titrant Ans a. b. . Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 18 NOTES /CALCULATIONS /ROUGH WORK ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ 19 Date: / / Experiment No. 4 Aim: To determine the molarity of the given hydrochloric acid (HCl) solution by using a standard solution of (0.05M) sodium carbonate (Na2CO3). Apparatus: Burette, pipette, burette stand, conical fl ask, white porcelain tile, etc. Chemicals: Standard solution of (0.05 M) Na2CO3, HCl solution, methyl orange indicator. Principle: This is an acidimetry titration. The titration is between strong acid (HCl) and weak base (Na2CO3). Procedure : 1. Wash the burette, pipette and conical fl ask with water. 2. Rinse the burette with given HCl solution and then fill the burette with HCl solution. Remove the air bubble from the nozzle and avoid leakage if any. 3. Adjust the level of the solution up to the zero mark carefully and fix it on burette stand. 4. Rinse the pipette with Sodium Carbonate solution. 5. Pipette out 10 mL of 0.05 M Sodium Carbonate solution and put it carefully in the conical fl ask. 6. Add two drops of methyl orange indicator to the solution in the conical fl ask. The solution becomes yellow in color. 7. Place the conical fl ask on the white porcelain tile below the burette. 8. Start adding HCl solution dropwise from the burette in the conical fl ask with continuous stirring, till the color of solution changes from yellow to orange pink. Stop adding HCl. This is end point of the titration. 9. Note this reading as ‘pilot’ reading. 10. Repeat the above procedure and take minimum three more correct burette readings. 11. Note down the constant burette readings ....... x mL (C.B.R.) Observation: 1. Solution in a burette 2. Solution by a pipette 3. Indicator 4. Color change i.e. end point 5. Chemical equation : : : : : Na2CO3 + 2 HCl 2NaCl + H2O + CO2 Observation Table: Burette reading Final Initial Difference Pilot reading ................. to ............mL Burette reading in mL I .............. II .............. 0.0 .............. 0.0 .............. 20 C.B.R. III .............. 0.0 .............. ............ (x) mL Calculations: From above chemical equation 1 mol of Na2CO3 combines with 2 mol of HCl ? 106 g of Na2CO3 = 73 g of HCl (Molar mass of Na2CO3 = 106 g mol-1, Molar mass of HCl = 36.5 g mol-1) 1. To calculate ‘g’ of HCl ? 1000 mL of 1M Na2CO3 { 73 g HCl ? 10 mL of 1M Na2CO3{ 0.73 g HCl ? 10 mL of 0.05M Na2CO3 { 0.0365 g HCl Therefore 0.0365 g HCl is present in ................ (x) mL of HCl solution. ? ....... (x) mL of HCl solution contains 0.0365 g HCl 1000 × 0.0365 ? 1000 mL of HCl solution will contain = ...........(x) g of HCl 2. To calculate molarity of HCl ? Molarity of HCl = = Space for calculation 1000 × 0.0365 ...........(x) × 36.5 1 ...........(x) Result: Solution Molarity HCl .................. M Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 21 MCQ Select [3] or underline the most appropriate answer from given alternatives of each sub question. 1. The indicator used in the titration of HCl and Na2CO3 is----a. phenolphthalein c. universal indicator b. methyl blue d. methyl orange 2. A student perform volumetric analysis experiment of HCl against 0.05M Na2CO3 solution, and record I, II and III burette readings 9.8 mL, 9.6 mL and 9.8 mL, respectively. The constant burette reading is.......... a. 9.6 mL b. 9.7 mL c. 9.8 mL d. 9.9 mL 3. In the reaction Na2CO3 + 2 HCl o 2 NaCl + H2O + CO2 ; 10 mL of 1M Na2CO3 contains ----grams of HCl (Molar mass: Na2CO3 = 106 g mol-1 and of HCl = 36.5 g mol-1) a. 0.73 g b. 0.365 g c. 3.65 g d. 7.3 g 4. In the titration of Na2CO3 (in burette) against HCl (in conical fl ask) the color change in conical fl ask is a. light orange b. blue c. yellow d. Colorless 5. In titration of Na2CO3 against HCl the burette usually filled with a. sodium carbonate c. hydrochloric acid b. sodium bicarbonate d. methyl orange Short answer question 1. Write the chemical reaction when Na2CO3(aq) is titrated against HCl (aq) in volumetric analysis? Ans 2. Why indicator cannot take part in a chemical reaction? Ans 3. Calculate the number of moles of HCl present in 500 mL of 0.1M HCl solution. Ans 4. What are different types of volumetric titration methods? Ans Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 22 NOTES /CALCULATIONS /ROUGH WORK ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ 23 Inorganic Qualitative Analysis Introduction: Qualitative analysis is a branch of chemistry which deals with finding the chemical composition of unknown substances. In inorganic qualitative analysis the process consists of finding out basic radical (cation) and acidic radical (anion) present in an inorganic compound. Qualitative analysis can be performed by using micro scale technique. i.e. quantity about 5 milligrams or volume 0.5 mL. Detection of one cation and one anion in a given salt: An ionic compound when dissolved in water gives positive ion and a negative ion. The positive ion or cation is also called as basic radical and a negative ion or anion is called acidic radical. In qualitative analysis, we are going to identify a basic radical and an acidic radical from a simple water soluble salt. 1. Basic radicals (Cations) Group Cations I II III A III B Pb2+ Cu2+ Al3+, Fe3+ Ni2+, Co2+, Zn2+ IV V VI Ba2+, Sr2+, Ca2+ Mg2+ NH4+ 2. Acidic radicals (Anions) Anions Cl-, Br-, I-, CO32-, SO32SO42-, PO43NO2NO3CH3COOC2O42- 3. Qualitative analysis of a salt involved the following steps. a. Preliminary tests b. Dry tests for basic radical (cations) c. Dry tests for acidic radical (anions) d. Preparation of the original solution e. Wet tests for basic radical (cations) f. Wet tests for acidic radical (anions) g. Result A. Preliminary tests: (General scheme) Test Nature Observation Inference Cl, Br, I, NO , SO 2 , etc. may be present. i. Crystalline (soluble in water) ii. Amorphous iii. Hygroscopic (moist) 3 4 Water insoluble salt may be present like CO32, S2. Chlorides or nitrates of Cu2+, Ni2+, Co2+, Ca2+ may be present Color of salt i. Blue ii. Green iii. Yellow or Brown iv. Pink or Violet v. Light pink or buff vi. White or colorless Cu2+ may be present Ni2+ may be present Fe3+ may be present Co2+ may be present Mn2+ may be present Pb2+, Al3+, Mn2+, Zn2+, Ba2+, Ca2+, Sr2+, Mg2+, NH4+ may be present Solubility Soluble in water Crystalline salt present 24 B. Dry Tests for Basic radicals (Cations) Test 1. Heating in a dry test tube:Take a small quantity of salt in a clean, dry test tube and heat it strongly. Observe the color of the residue and gas evolved. 2. Test for NH4+ Salt + NaOH, heat gently hold moist turmeric paper near the mouth of test tube 3. Charcoal cavity test: Take the salt and solid Na2CO3 in the ratio 1:2 on watch glass, add few drops of water and prepare a paste, place this in charcoal cavity and heat it with a blow pipe in a reducing fl ame. Observations i. Decrepitation (cracking noise) ii. Salt fuses Chloride or nitrites of Na+, Pb2+, Ba2+ may be present Salts of Ca2+ and hydrated salt may be present. Salt containing water of crystallization may be present. iii. Water vapors condense on the cooler part of the test tube iv. White sublimate NH4+ may be present. v. Residue left in the test tube Al3+, Zn2+, Ba2+, Ca2+, NH4+ a. White infusible may be present residue Cu2+, Ni2+, Co2+, Fe3+ may be b. Colored/ black present residue vi. Colored residue Hot Cold yellow white Zn2+ may be present Pb2+ may be present brown yellow vii. Blue salt turns white Crystalline CuSO4 may be present + Smell of NH3 gas, turning NH4 may be present. moist turmeric paper reddish brown Cu2+ may be present i. Red scales Pb2+ may be present ii. Metallic bead with yellow incrustation Pb2+ may be present iii. Decripitation iv. White incrustations NH4+ may be present Zn2+, Al3+, Mg2+, Ba2+, Sr2+ v. White infusible Ca2+ residue may be present vi. Colored or Black, residue vii. Residue yellow when hot and white when cold 4. Cobalt Nitrate Test: If white infusible residue is obtained in charcoal cavity test, add two drops of cobalt nitrate solution on the white residue and heat in the blue fl ame. Inference i. Residue turns blue ii. Residue turns pink iii Residue turns green iv Residue turns grey 25 Cu2+, Ni2+, Fe3+, Co2+ may be present Zn2+ may be present Al3+may be present Mg2+ may be present Zn2+ may be present Ba2+, Ca2+ may be present 5. Flame test: Clean a platinum wire with conc. HCl. Moisten a small quantity of the substance with concentrated HCl on watch glass. Dip the cleaned platinum wire in it and heat it in oxidizing fl ame. (non - luminous) and observe the color of the fl ame 6. Borax bead test: [For colored salt only] Make a small loop at the end of a clean platinum wire heat it strongly and dip it in borax powder.Heat it again till a glossy bead is obtained. Now touch the hot bead with a small crystal of the salt and heat it again in oxidizing (blue) fl ame. Observe the color of the bead. i. Bluish green ii. Apple green iii. Brick red iv Bluish white v. No distinct color Cu2+ may be present. Ba2+may be present Ca2+may be present Pb2+ may be present Ba2+, Ca2+ may be absent. i. Greenish blue ii. Reddish brown iii. Dark blue Cu2+ may be present Ni2+ may be present Co2+ may be present C. Dry tests for anions (Acidic radicals) Test i. Action of dil HCl: Salt + dil HCl. Observation Inference i. colorless gas with brisk effervescence CO32- may be present in cold, turning lime water milky ii. colorless gas with smell of burning Sulfur turning acidifid K2Cr2O7 paper green SO32- may be present NO2- may be present i. colorless gas, giving white dense Cl- may be present fumes glass rod dipped in NH4OH iii. Redish brown gas ii. Action of conc. H2SO4: Salt + conc. H2SO4+ heat ii. Brown gas evolve turning moist Br- may be present starch paper yellow iii. Brown gas evolve after heating NO3- may be present does not turn starch paper yellow iv. violet gas evolved turning starch I- may be present paper blue v. colorless gas with smell of vinegar CH3COO- may be present iii. Action of MnO2 and conc. Colorless gas or greenish yellow gas Cl may be present turning moist blue litmus paper red H2SO4: Salt + a pinch of MnO2 + conc. and then bleaches H2SO4 and heat Reddish brown gas turning starch Br- may be present paper yellowish brown Light brown fumes, no action on starch NO3- may be present paper Violet gas turning starch paper bluish I- may be present black 26 iv. Cu-foil test: (If brown gas is obtained in the above test then only perform this test) Salt + Cu-foil + conc. H2SO4 and heat strongly Brown gas, solution turns green and no action on starch paper NO3- may be present (Note: If the anion is not detected in above dry test, then salt may contain SO42- or PO43-) D. Preparation of solution (Original Solution): Dissolve about 0.5 gm of salt in 20 mL of water in a 50 ml beaker. This is called original solution (O.S.) E. Wet test for basic radical (cations) Detection of groups Test 1. O.S. + dil. HCl Observations White ppt No ppt Black ppt Inference Group I (Pb2+) present Group I absent Group II (Cu2+) present No ppt Group II absent 3. O.S. + NH4Cl + NH4OH till alkaline White / brown ppt Group IIIA (Al3+/ Fe3+) present No ppt Group III A absent 4. O.S.+ NH4Cl + NH4OH till alkaline + H2S gas / H2S water solution White / black / pink ppt Group IIIB (Zn2+/ Ni2+/ Co2+ / Mn2+) present Group IIIB absent Group IV (Ca2+/ Ba2+/ Sr2+) present Group IV absent 2. O.S. + dil. HCl + H2S gas / H2S water solution No ppt White ppt No ppt 5. O.S. + NH4Cl + NH4OH till alkaline + saturated solution of (NH4)2CO3 6. O.S. + NH4Cl + NH4OH till White ppt alkaline + Na2HPO4 No ppt 7. If all the above groups are Hence absent Group V (Mg2+) present Group V absent Group VI (NH4+) present Analysis of Group: After detection of a particular group do analysis of that group. Analysis of Group I Test O. S.+ dil HCl Observations Inference White ppt Pb2+ present C.T. for Pb2+ (Lead) 1. O.S.+ KI Solution Yellow ppt Pb2+ confirmed 2. O.S. + K2CrO4 Solution Yellow ppt Pb2+ confirmed Analysis of Group II Test O.S. + dil HCl + H2S gas / sol. C.T. for Cu (Cupric) 1. O.S. + NaOH in excess 2. O.S. + CH3COOH + K4Fe(CN)6 Observations Black ppt Inference Cu2+ present Blue ppt Cu2+ confirmed Chocolate brown ppt Cu2+ confirmed 2+ 27 Pale blue ppt Cu2+ confirmed Observations Inference 3. O.S. + NH4OH excess Analysis of Group IIIA Test O.S. + NH4Cl + NH4OH till alkaline i) White gelatinous ppt Al3+ Present ii) Brown ppt Fe3+ Present C.T. for Al3+ (Aluminium) 1. O.S .+ NaOH White ppt soluble in excess of Al3+ confirmed NaOH and reobtained by adding NH4Cl 2. O.S. + Na2HPO4 White ppt Al3+ confirmed C.T. for Fe3+ (Ferric) O.S. + NH4SCN Blood red coloration Fe3+ confirmed O.S. + K4[Fe(CN)6] Deep blue ppt Fe3+ confirmed O.S. + NaOH Green precipitate turns reddish Fe3+ confirmed brown on exposed to air Analysis of Group III B Test O.S.+ NH4Cl + NH4OH + H2S gas / water O.S. + NaOH Observations Inference i) Black ppt Ni2+ or Co2+ present ii) White ppt Zn2+ present iii) Buff ppt Mn2+ present Greenish ppt Ni2+ is present Blue ppt Co2+ is present OR Green / Bluish green Ni2+ is present Pink / Light pink Co2+ is present C.T. for Ni2+ (Nickel) 1.O.S. + NH4OH + dimethylglyoxime till alkaline Scarlet red ppt Ni2+ confirmed 2.O.S. + NaOH Light green ppt soluble in NH4Cl Ni2+ confirmed 3.O.S. + K3Fe(CN)6 (potassium ferricyanide) Yellowish brown ppt Observe the color of O.S. Ni2+ confirmed C.T. for Co2+ (Cobalt) i. O.S. + NH4OH + K3Fe(CN)6 Reddish brown ppt Co2+ confirmed i. O.S. + NH4SCN + acetone Blue solution Co2+ confirmed ii. O.S. + NaOH solution Blue ppt turns pink brown on Co2+ confirmed heating 28 C.T. for Zn2+ (Zinc) i. O.S. + dil. HCl +K4Fe(CN)6 White ppt Zn2+ confirmed i. O.S. + Na2HPO4 solution White ppt soluble in excess Zn2+ confirmed C.T. for Mn2+ (Manganese) Fleshy ppt i. O.S. + Na2HPO4 solution violet coloration i. O.S. + conc.HNO3+ PbO2, heat and dilute with water White ppt turns brown on iii. O.S. + NH4OH exposure to air Analysis of Group IV Test i. O.S. + K2CrO4 ii. O. S.+ saturated solution of (NH4)2SO4 and boil C.T. for Ba2+ (Barium) i. O.S.+ K2CrO4 ii. O.S.+ dil H2SO4 Inference Ba present ii)No ppt Sr2+ or Ca2+ present i) White ppt Sr2+ present ii) No ppt Ca2+ present 2+ Ba2+ confirmed Yellow ppt White ppt Test Ba2+ confirmed Sr2+ confirmed Sr2+ confirmed Sr2+ confirmed Observation White ppt Test C.T. for Mg (Magnesium) i. O.S.+ 2 drops of titan yellow solution+ 3 drops of 2N NaOH ii. O.S.+ Hypoiodite reagent 2+ Mn2+ confirmed Observation i) Yellow ppt C.T. for Sr2+ (Strontium) 1. O.S. + (NH4)2 SO4, boil White ppt Crimson color to the fl ame 2. O.S. + 2 to 3 drops of conc. HCl and take it on platinum foil 3.O.S. + conc. HCl and take Brownish red color spot drop of it on a paper of add a drop of sodium rhodizonate solution Analysis of Group V. O.S.+ NH4Cl + NH4OH + Na2HPO4 Mn2+ confirmed Mn2+ confirmed Inference Mg present 2+ Observation Rose red color or ppt Inference Mg confirmed Reddish brown color or ppt Mg2+ confirmed 2+ (Hypoiodite reagent: NaOH solution + equal amount of KI solution + Iodine solution till the solution becomes yellow) 29 Analysis of Group VI Test i. O.S.+ NaOH solution. Heat Observation Inference Smell of NH3 NH4+ present C.T. for NH4+ (Ammonium) i. O.S. +2 drops of Nessler’s Brown precipitate reagent (2 drops of HgCl2 + KI drop by drop till scarlet red ppt formed just dissolves + equal amount of NaOH) ii. O.S. + picric acid (Rub test tube with glass rod) NH4 +confirmed Yellow ppt NH4+ confirmed F. Wet test for acidic radicals: Detection of acidic radical from water solution: 1. Wet tests for CO32–, SO32–, Cl–, Br –, I– 1. O.S. + AgNO3 i. White ppt soluble in dil.HNO3 CO32-present acid with effervescence of CO2 which turns lime water milky SO32-present ii. White ppt soluble in dil. HNO3 acid with evolution of SO2 gas which decolorizes KMnO4 solution iii. White or yellow ppt insoluble in dil HNO3 Cl-, Br-, I- are present iv. If no ppt Cl-, Br-, I-, CO32- SO 2-are absent 3 Distinction between halides (Cl , Br , I ): Note: (Perform this test only if ppt is obtained for AgNO3 which is insoluble in dil.HNO3) Test O.S. + Chloroform + Cl2 water in excess (shake well) Observations Inference i. Chloroform layer is colorless Cl- present ii. Chloroform layer is yellow (or Br-present yellowish brown) iii. Chloroform layer is violet/ I-present pink Note: (If one of the halide radical is present then further analysis is not necessary. Perform confirmatory test for that detected radical.) 2. Wet test for SO42– and PO43– (This test is required to perform only, if ppt is NOT obtained in AgNO3 test) Test O.S. + Ba(NO3)2 Observations i. White ppt, insoluble in dil HNO3 Inference SO42 present ii. White ppt, soluble in dil HCl or dil HNO3 without effervescence 30 PO42 present _ 3. WET TEST FOR NO2 Test O.S. + dil.H2SO4 + FeSO4 solution Observations i. Deep brown coloration Inference NO2 present - ii. No deep brown coloration NO2- present Observations i. Evolution of NO2 gas which turns starch iodidc paper black Inference NO3- present ii. If no evolution of gas NO3- present _ 4. WET TEST FOR NO3 Test O.S. + 3-4 drops of conc.H2SO4+ 2-3 drops of diphenyl amine 5. WET TEST FOR CH3COO _ Test O.S. + FeCl3 solution 6. WET TEST FOR C2O42 Observations _ Red color appears. Test Inference CH3COO- present Observations O.S. +dil. Acetic acid + CaCl2 White ppt is obtained Inference C2O42- present Confirmative tests for acidic radicals C.T. for CO32 [Carbonate] Test i. O.S. + AgNO3 solution Observations White ppt soluble in dil. HNO3 Inference CO32- confirmed ii. O.S. + Ba(NO3)2 solution White ppt soluble in dil. HCl CO32- confirmed C.T. for SO32- [Sulphite] Test Observations i. O.S. + dil.HCl + K2Cr2O7 sol. Green coloration Inference SO32- confirmed ii. O.S. + dil.HCl + 1-2 drops of KMnO4 solution iii. O.S. + BaCl2 solution Pink coloration of KMnO4 dissapper SO32- confirmed White ppt soluble in dil. HNO3 SO32- confirmed iv. O.S. + Ba(NO3)2 solution White ppt soluble in dil. HCl SO32- confirmed Test i. O.S. + dil.HCl+ 2-3drops of FeSO4solution Observations Brown coloration Inference NO2 confirmed ii. O.S. + AgNO3 solution White crystalline ppt NO2- confirmed iii. O.S. + Acetic acid + FeSO4solution Brown coloration NO2- confirmed C.T. for NO2[Nitrite] - C.T. for Cl [Chloride] Test Observations Inference i. O.S.+ MnO2 + 2-3 drops of Greenish yellow gas evolves that turns Cl confirmed moist blue litmus red and then bleaches it conc. H2SO4 and heat 31 iii. O.S. + Lead acetate White ppt Cl- confirmed C.T. for Br [Bromide] Test i. O.S. + MnO2 + conc. H2SO4 and heat ii. O.S.+ Lead acetate solution Observation Inference Excess red brown gas evolves Br- confirmed Pale yellow ppt soluble in hot water Br- confirmed C.T. for I [Iodide] Test Observation i. O.S. + HgCl2 solution in excess Scarlet ppt ii. O.S.+ Lead acetate solution C.T. for NO3 [Nitrate] Test Yellow ppt Inference I- confirmed I- confirmed Observation i. O.S. + diphenyl amine + conc. Intense blue color H2SO4 Inference NO3 confirmed - ii. O.S. + conc. H2SO4 heat and Brown ring forms at the junction NO3- confirmed of two liquids cool, add freshly prepared FeSO4 along sides of the test tube C.T. for CH3COO [Acetate] Test i. O.S. + Neutral FeCl3 iii. O.S. + Ethyl alcohol and heat carefully Observation Blood red color Fruity smell Inference CH3COO- confirmed CH3COO- confirmed C.T. for C2O42– [Oxalate] Test i. O.S. + Hot acidified KMnO4 Observation Inference Decoloration of KMnO4 C2O42- confirmed C.T. for SO42 [Sulfate] Test Observation Inference 2i. O.S. + Acetic acid + Lead acetate White ppt insoluble in dil. HNO3 SO4 confirmed but soluble in hot ammonium solution acetate White ppt of BaSO4 SO42- confirmed ii. O.S. + BaCl2 solution SO42- confirmed iii. O.S. + 2 drops of KMnO4 sol. Pink ppt + BaCl2 solution C.T. for PO43- [Phosphate] Test Observation i. O.S. + Ammonium molybdate Canary yellow ppt solution + conc. HNO3 and heat ii. O.S. + Neutral FeCl3 solution Inference PO4 confirmed 3- Yellowish white ppt soluble in dil. PO43- confirmed HCl 32 iii. O.S. + Ba(NO3)2 solution White ppt soluble in dil. HCl PO43- confirmed Result:- Given salt contains 1. Basic radical ....................................................... 2. Acidic radical ...................................................... 3. Molecular formula of salt ................................. 4. Hence the name of the salt ................................ .................................MCQ Select [3] or underline the most appropriate answer from given alternatives of each sub question. 1. The elements of following groups are precipitated in the form of sulfides? a. I and II b. II and IIIA c. II and IIIB d. IIIB and IV 2. Which of the following Cation (basic radical) belongs to Group IV? a. Cu2+ b. Ba2+ c. Al3+ d. Mg2+ 3. A salt is heated with NaOH produce ammonia gas, which terns color of moist turmeric paper a. Reddish brown b. Blue c. Black d. Yellow 4. What are the group reagents of group VI? a. Dil.HCl b. NH4Cl and NH4OH c. NH4Cl, NH4OH and Na2HPO4 d. No group reagent 5. The chemical used in the distinction test of chloride, bromide and iodide anions is a. AgNO3 b. Ba(NO3)2 c. Cl2 water + CHCl3 d. (CH3COO)2 Pb Short answer questions 1. What is Nessler’s reagent? Ans 2. Name any two Colored basic radicals? Ans 3. What is Color of cobalt salt? Ans 4. Name basic radicals which are absent if given salt is white? Ans 5. Blue crystals of copper sulfate becomes colorless on heating. Why? Ans 33 6. What are acidic radicals? Ans 7. Write the names of chemicals used in preparation of hypoiodite reagent? Ans 8. Heating is necessary for dry test of nitrate anion, why? Ans 9. What is decripitation? Ans 10. Which salts decripitates on heating? Ans 11. Why do we keep silver nitrate in colored bottle? Ans 12. Which acidic radicals produce fruity smell? Ans Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 34 NOTES /CALCULATIONS /ROUGH WORK ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ 35 Date: / / Experiment No. 5 Inorganic Qualitative Analysis (Salt no.1) Aim: Analyse one basic (cation) and one acidic (anion) radical from given inorganic salt. Apparatus: Test tubes, test tube stand, spatula, glass rod, watch glass, beaker, burner, etc. A. Preliminary tests: (General scheme) Test Observation Inference Observations Inference Nature Color of salt Solubility B. Dry tests for basic radicals (Cations) Test 1. Heating in a dry test tube:Take a small quantity of salt in a clean, dry test tube and heat it strongly. Observe the color of the residue and gas evolved. 2. Test for NH4+ Salt + NaOH, heat gently, hold moist turmeric paper near the mouth of test tube. 3. Charcoal cavity test: Take the salt and solid Na2CO3 in the ratio 1:2 on watch glass, add few drops of water and prepare a paste, place this in charcoal cavity and heat it with a blow pipe in a reducing fl ame. 4. Cobalt Nitrate Test: If white infusible residue is obtained in charcoal cavity test, add two drops of cobalt nitrate solution on the white residue and heat in the blue fl ame. 36 5. Flame test: Clean a platinum wire with conc. HCl. Moisten a small quantity of the substance with concentrated HCl on watch glass. Dip the cleaned platinum wire in it and heat it in oxidizing fl ame (non - luminous) and observe the color of the fl ame 6. Borax bead test: [For colored salt only] Make a small loop at the end of a clean platinum wire heat it strongly and dip it in borax powder.Heat it again till a glossy bead is obtained. Now touch the hot bead with a small crystal of the salt and heat it again in oxidizing (blue) fl ame. Observe the color of the bead. C. Dry tests for acidic radicals (Anions) Test Observation Inference i. Action of dil HCl Salt + dil HCl. ii. Action of conc. H SO4: Salt + conc. H2SO4+ heat 2 iii. Action of MnO2 and conc.H2SO4: Salt + a pinch of MnO2 + conc. H2SO4 and heat iv. Cu-foil test: (If brown gas is obtained in the above test then only perform this test) Salt + Cu-foil + conc. H2SO4 and heat strongly Note: (If the anion is not detected in above dry test, then salt may contain SO42- or PO43-) 37 D. Preparation of solution (Original Solution): Dissolve about 0.5 gm of salt in 20 mL of water in a 50 mL beaker. This is called original solution (O.S.) E. Wet test for basic radical (cations) Detection of groups Test Observations Inference 1. O.S. + dil. HCl 2. O.S. + dil. HCl + H2S gas / H2S water solution 3. O.S. + NH4Cl + NH4OH till alkaline 4. O.S.+ NH4Cl + NH4OH till alkaline + H2S gas /H2S water solution 5. O.S. + NH4Cl + NH4OH till alkaline + saturated solution of (NH4)2CO3 6. O.S. + NH4Cl + NH4OH till alkaline + Na2HPO4 7. If all the above groups are absent Analysis of Group: After detection of a particular group do analysis of that group. Analysis of Group .......... Test Observations C.T. for............. 1. 2. F. Wet test for acidic radicals: Detection of acidic radical from water solution: 38 Inference 1. Wet tests for CO32–, SO32–, Cl–, Br –, I– 1. O.S. + AgNO3 Distinction between halides (Cl–, Br–, I–): Note: (Perform this test only if ppt is obtained for AgNO3 which is insoluble in dil. HNO3) Test Observation Inference O.S. + Chloroform + Cl2 water in excess (shake well) Note: (If one of the halide radical is present then further analysis is not necessary. Perform confirmatory test for that detected radical.) 2. Wet test for SO42– and PO43– (This test is required to perform only, if ppt is NOT obtained in AgNO3 test) Test Observation Inference Observation Inference Observation Inference Observation Inference O.S. + Ba(NO3)2 3. WET TEST FOR NO2– Test O.S. + dil. H2SO4 + FeSO4 solution 4. WET TEST FOR NO3– Test O.S. + 3-4 drops of conc.H2SO4 + 2-3 drops of diphenyl amine 5. WET TEST FOR CH3COO Test O.S. + FeCl3 solution 39 6. WET TEST FOR C2O42– Test Observation Inference Observation Inference O.S. +dil. Acetic acid + CaCl2 C.T. for ................................ Test 1. 2. Result:- Given inoragnic salt no. 1 contains following 1. Basic radical .................................. ................ 2. Acidic radical........................................................ 3 . Molecular formula of the salt.......................................... 4. Hence the name of the salt........................................................................ Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 40 Date: / / Experiment No. 6 Inorganic Qualitative Analysis (Salt no. 2) Aim: Analyse one basic (cation) and one acidic (anion) radical from given inorganic salt. Apparatus: Test tubes, test tube stand, spatula, glass rod, watch glass, beaker, burner, etc. A. Preliminary tests: (General scheme) Test Observation Inference Observations Inference Nature Color of salt Solubility B. Dry tests for basic radicals (Cations) Test 1. Heating in a dry test tube:Take a small quantity of salt in a clean, dry test tube and heat it strongly. Observe the color of the residue and gas evolved. 2. Test for NH4+ Salt + NaOH, heat gently, hold moist turmeric paper near the mouth of test tube. 3. Charcoal cavity test: Take the salt and solid Na2CO3 in the ratio 1:2 on watch glass, add few drops of water and prepare a paste, place this in charcoal cavity and heat it with a blow pipe in a reducing fl ame. 4. Cobalt Nitrate Test: If white infusible residue is obtained in charcoal cavity test, add two drops of cobalt nitrate solution on the white residue and heat in the blue fl ame. 41 5. Flame test: Clean a platinum wire with conc. HCl. Moisten a small quantity of the substance with concentrated HCl on watch glass. Dip the cleaned platinum wire in it and heat it in oxidizing fl ame (non - luminous) and observe the color of the fl ame. 6. Borax bead test: [For colored salt only] Make a small loop at the end of a clean platinum wire heat it strongly and dip it in borax powder.Heat it again till a glossy bead is obtained. Now touch the hot bead with a small crystal of the salt and heat it again in oxidizing (blue) fl ame. Observe the color of the bead. C. Dry tests for acidic radicals (Anions) Test Observation Inference i. Action of dil HCl Salt + dil HCl. ii. Action of conc. H SO4: Salt + conc. H2SO4+ heat 2 iii) Action of MnO2 and conc.H2SO4: Salt + a pinch of MnO2 + conc. H2SO4 and heat iv) Cu-foil test: (If brown gas is obtained in the above test then only perform this test) Salt + Cu-foil + conc. H2SO4 and heat strongly Note: (If the anion is not detected in above dry test, then salt may contain SO42- or PO43-) 42 D. Preparation of solution (Original Solution): Dissolve about 0.5 gm of salt in 20 mL of water in a 50 mL beaker. This is called original solution (O.S.) E. Wet test for basic radical (cations) Detection of groups Test Observations Inference 1. O.S. + dil. HCl 2. O.S. + dil. HCl + H2S gas / H2S water solution 3. O.S. + NH4Cl + NH4OH till alkaline 4. O.S.+ NH4Cl + NH4OH till alkaline + H2S gas/ H2S water solution 5. O.S. + NH4Cl + NH4OH till alkaline + saturated solution of (NH4)2CO3 6. O.S. + NH4Cl + NH4OH till alkaline + Na2HPO4 7. If all the above groups are absent Analysis of Group: After detection of a particular group do analysis of that group. Analysis of Group .......... Test Observations C.T. for............. 1. 2. 43 Inference F. Wet test for acidic radicals: Detection of acidic radical from water solution: 1. Wet tests for CO32–, SO32–, Cl–, Br –, I– 1. O.S. + AgNO3 Distinction between halides (Cl–, Br–, I–): Note: (Perform this test only if ppt is obtained for AgNO3 which is insoluble in dil. HNO3) Test Observation Inference O.S. + Chloroform + Cl2 water in excess (shake well) Note: (If one of the halide radical is present then further analysis is not necessary. Perform confirmatory test for that detected radical.) 2. Wet test for SO42– and PO43– (This test is required to perform only, if ppt is NOT obtained in AgNO3 test) Test Observation Inference Observation Inference Observation Inference Observation Inference O.S. + Ba(NO3)2 3. WET TEST FOR NO2– Test O.S. + dil. H2SO4 + FeSO4 solution 4. WET TEST FOR NO3– Test O.S. + 3-4 drops of conc. H2SO4 + 2-3 drops of diphenyl amine 5. WET TEST FOR CH3COO Test O.S. + FeCl3 solution 44 6. WET TEST FOR C2O42– Test Observation Inference Observation Inference O.S. +dil. Acetic acid + CaCl2 C.T. for ................................ Test 1. 2. Result:- Given inoragnic salt no. 2 contains following 1. Basic radical .................................. ................ 2. Acidic radical........................................................ 3 . Molecular formula of the salt.......................................... 4. Hence the name of the salt........................................................................ Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 45 Date: / / Experiment No. 7 Inorganic Qualitative Analysis (Salt no. 3) Aim: Analyse one basic (cation) and one acidic (anion) radical from given inorganic salt. Apparatus: Test tubes, test tube stand, spatula, glass rod, watch glass, beaker, burner, etc. A. Preliminary tests: (General scheme) Test Observation Inference Observation Inference Nature Color of salt Solubility B. Dry tests for basic radicals (Cations) Test 1. Heating in a dry test tube:Take a small quantity of salt in a clean, dry test tube and heat it strongly. Observe the color of the residue and gas evolved. 2. Test for NH4+ Salt + NaOH, heat gently, hold moist turmeric paper near the mouth of test tube. 3. Charcoal cavity test: Take the salt and solid Na2CO3 in the ratio 1:2 on watch glass, add few drops of water and prepare a paste, place this in charcoal cavity and heat it with a blow pipe in a reducing fl ame. 4. Cobalt Nitrate Test: If white infusible residue is obtained in charcoal cavity test, add two drops of cobalt nitrate solution on the white residue and heat in the blue fl ame. 46 5. Flame test: Clean a platinum wire with conc. HCl. Moisten a small quantity of the substance with concentrated HCl on watch glass. Dip the cleaned platinum wire in it and heat it in oxidizing fl ame (non - luminous) and observe the color of the fl ame. 6. Borax bead test: [For colored salt only] Make a small loop at the end of a clean platinum wire heat it strongly and dip it in borax powder.Heat it again till a glossy bead is obtained. Now touch the hot bead with a small crystal of the salt and heat it again in oxidizing (blue) fl ame. Observe the color of the bead. C. Dry tests for acidic radicals (Anions) Test Observation Inference i. Action of dil HCl Salt + dil HCl. ii. Action of conc. H SO4: Salt + conc. H2SO4+ heat 2 iii. Action of MnO2 and conc.H2SO4: Salt + a pinch of MnO2 + conc. H2SO4 and heat iv. Cu-foil test: (If brown gas is obtained in the above test then only perform this test) Salt + Cu-foil + conc. H2SO4 and heat strongly Note: (If the anion is not detected in above dry test, then salt may contain SO42- or PO43-) 47 D. Preparation of solution (Original Solution): Dissolve about 0.5 gm of salt in 20 mL of water in a 50 mL beaker. This is called original solution (O.S.) E. Wet test for basic radical (cations) Detection of groups Test Observation Inference 1. O.S. + dil. HCl 2. O.S. + dil. HCl + H2S gas / H2S water solution 3. O.S. + NH4Cl + NH4OH till alkaline 4. O.S.+ NH4Cl + NH4OH till alkaline + H2S gas / H2S water solution 5. O.S. + NH4Cl + NH4OH till alkaline + saturated solution of (NH4)2CO3 6. O.S. + NH4Cl + NH4OH till alkaline + Na2HPO4 7. If all the above groups are absent Analysis of Group: After detection of a particular group do analysis of that group. Analysis of Group .......... Test Observation C.T. for............. 1. 2. 48 Inference F. Wet test for acidic radicals: Detection of acidic radical from water solution: 1. Wet tests for CO32–, SO32–, Cl–, Br –, I– 1. O.S. + AgNO3 Distinction between halides (Cl, Br, I): Note: (Perform this test only if ppt is obtained for AgNO3 which is insoluble in dil.HNO3) Test Observation Inference O.S. + Chloroform + Cl2 water in excess (shake well) Note: (If one of the halide radical is present then further analysis is not necessary. Perform confirmatory test for that detected radical.) 2. Wet test for SO42– and PO43– (This test is required to perform only, if ppt is NOT obtained in AgNO3 test) Test Observation Inference Observation Inference Observation Inference Observation Inference O.S. + Ba(NO3)2 3. WET TEST FOR NO2– Test O.S. + dil. H2SO4 + FeSO4 solution 4. WET TEST FOR NO3– Test O.S. + 3-4 drops of conc.H2SO4 + 2-3 drops of diphenyl amine 5. WET TEST FOR CH3COO Test O.S. + FeCl3 solution 49 6. WET TEST FOR C2O42– Test Observation Inference Observation Inference O.S. +dil. Acetic acid + CaCl2 C.T. for ................................ Test 1. 2. Result:- Given inoragnic salt no. 3 contains following 1. Basic radical .................................. ................ 2. Acidic radical........................................................ 3 . Molecular formula of the salt.......................................... 4. Hence the name of the salt........................................................................ Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 50 Date: / / Experiment No. 8 Inorganic Qualitative Analysis (Salt no. 4) Aim: Analyse one basic (cation) and one acidic (anion) radical from given inorganic salt. Apparatus: Test tubes, test tube stand, spatula, glass rod, watch glass, beaker, burner, etc. A. Preliminary tests: (General scheme) Test Observation Inference Observations Inference Nature Color of salt Solubility B. Dry tests for basic radicals (Cations) Test 1. Heating in a dry test tube:Take a small quantity of salt in a clean, dry test tube and heat it strongly. Observe the color of the residue and gas evolved. 2. Test for NH4+ Salt + NaOH, heat gently, hold moist turmeric paper near the mouth of test tube. 3. Charcoal cavity test: Take the salt and solid Na2CO3 in the ratio 1:2 on watch glass, add few drops of water and prepare a paste, place this in charcoal cavity and heat it with a blow pipe in a reducing fl ame. 4. Cobalt Nitrate Test: If white infusible residue is obtained in charcoal cavity test, add two drops of cobalt nitrate solution on the white residue and heat in the blue fl ame. 51 5. Flame test: Clean a platinum wire with conc. HCl. Moisten a small quantity of the substance with concentrated HCl on watch glass. Dip the cleaned platinum wire in it and heat it in oxidizing fl ame (non - luminous) and observe the color of the fl ame. 6. Borax bead test: [For colored salt only] Make a small loop at the end of a clean platinum wire heat it strongly and dip it in borax powder.Heat it again till a glossy bead is obtained. Now touch the hot bead with a small crystal of the salt and heat it again in oxidizing (blue) fl ame. Observe the color of the bead. C. Dry tests for acidic radicals (Anions) Test Observations Inference i. Action of dil HCl Salt + dil HCl. ii. Action of conc. H SO4: Salt + conc. H2SO4+ heat 2 iii. Action of MnO2 and conc.H2SO4: Salt + a pinch of MnO2 + conc. H2SO4 and heat iv. Cu-foil test: (If brown gas is obtained in the above test then only perform this test) Salt + Cu-foil + conc. H2SO4 and heat strongly Note: (If the anion is not detected in above dry test, then salt may contain SO42- or PO43-) 52 D. Preparation of solution (Original Solution): Dissolve about 0.5 gm of salt in 20 mL of water in a 50 mL beaker. This is called original solution (O.S.) E. Wet test for basic radical (cations) Detection of groups Test Observations Inference 1. O.S. + dil. HCl 2. O.S. + dil. HCl + H2S gas / H2S water solution 3. O.S. + NH4Cl + NH4OH till alkaline 4. O.S.+ NH4Cl + NH4OH till alkaline + H2S gas /H2S water solution 5. O.S. + NH4Cl + NH4OH till alkaline + saturated solution of (NH4)2CO3 6. O.S. + NH4Cl + NH4OH till alkaline + Na2HPO4 7. If all the above groups are absent Analysis of Group: After detection of a particular group do analysis of that group. Analysis of Group .......... Test Observation C.T. for............. 1. 2. 53 Inference F. Wet test for acidic radicals: Detection of acidic radical from water solution: 1. Wet tests for CO32–, SO32–, Cl–, Br –, I– 1. O.S. + AgNO3 Distinction between halides (Cl–, Br–, I–): Note: (Perform this test only if ppt is obtained for AgNO3 which is insoluble in dil. HNO3) Test Observation Inference O.S. + Chloroform + Cl2 water in excess (shake well) Note: (If one of the halide radical is present then further analysis is not necessary. Perform confirmatory test for that detected radical.) 2. Wet test for SO42– and PO43– (This test is required to perform only, if ppt is NOT obtained in AgNO3 test) Test Observation Inference O.S. + Ba(NO3)2 3. WET TEST FOR NO2– Test Observation Inference O.S. + dil. H2SO4 + FeSO4 solution 4. WET TEST FOR NO3– Test Observation Inference Observation Inference O.S. + 3-4 drops of conc.H2SO4 + 2-3 drops of diphenyl amine 5. WET TEST FOR CH3COO Test O.S. + FeCl3 solution 54 6. WET TEST FOR C2O42– Test Observation Inference Observations Inference O.S. +dil. Acetic acid + CaCl2 C.T. for ................................ Test 1. 2. Result:- Given inoragnic salt no. 4 contains following 1. Basic radical .................................. ................ 2. Acidic radical........................................................ 3 . Molecular formula of the salt.......................................... 4. Hence the name of the salt........................................................................ Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 55 Date: / / Experiment No. 9 Inorganic Qualitative Analysis (Salt no. 5) Aim: Analyse one basic (cation) and one acidic (anion) radical from given inorganic salt. Apparatus: Test tubes, test tube stand, spatula, glass rod, watch glass, beaker, burner, etc. A. Preliminary tests: (General scheme) Test Observation Inference Observations Inference Nature Color of salt Solubility B. Dry tests for basic radicals (Cations) Test 1. Heating in a dry test tube:Take a small quantity of salt in a clean, dry test tube and heat it strongly. Observe the color of the residue and gas evolved. 2. Test for NH4+ Salt + NaOH, heat gently, hold moist turmeric paper near the mouth of test tube. 3. Charcoal cavity test: Take the salt and solid Na2CO3 in the ratio 1:2 on watch glass, add few drops of water and prepare a paste, place this in charcoal cavity and heat it with a blow pipe in a reducing fl ame. 4. Cobalt Nitrate Test: If white infusible residue is obtained in charcoal cavity test, add two drops of cobalt nitrate solution on the white residue and heat in the blue fl ame. 56 5. Flame test: Clean a platinum wire with conc. HCl. Moisten a small quantity of the substance with concentrated HCl on watch glass. Dip the cleaned platinum wire in it and heat it in oxidizing fl ame (non - luminous) and observe the color of the fl ame. 6. Borax bead test: [For colored salt only] Make a small loop at the end of a clean platinum wire heat it strongly and dip it in borax powder.Heat it again till a glossy bead is obtained. Now touch the hot bead with a small crystal of the salt and heat it again in oxidizing (blue) fl ame. Observe the color of the bead. C. Dry tests for acidic radicals (Anions) Test Observations i. Action of dil HCl Salt + dil HCl. ii. Action of conc. H SO4: Salt + conc. H2SO4+ heat 2 iii. Action of MnO2 and conc.H2SO4: Salt + a pinch of MnO2 + conc. H2SO4 and heat iv. Cu-foil test: (If brown gas is obtained in the above test then only perform this test) Salt + Cu-foil + conc. H2SO4 and heat strongly 57 Inference Note: (If the anion is not detected in above dry test, then salt may contain SO42- or PO43-) D. Preparation of solution (Original Solution): Dissolve about 0.5 gm of salt in 20 mL of water in a 50 mL beaker. This is called original solution (O.S.) E. Wet test for basic radical (cations) Detection of groups Test Observations Inference 1. O.S. + dil. HCl 2. O.S. + dil. HCl + H2S gas/ H2S water solution 3. O.S. + NH4Cl + NH4OH till alkaline 4. O.S.+ NH4Cl + NH4OH till alkaline + H2S gas/ H2S water solution 5. O.S. + NH4Cl + NH4OH till alkaline + saturated solution of (NH4)2CO3 6. O.S. + NH4Cl + NH4OH till alkaline + Na2HPO4 7. If all the above groups are absent Analysis of Group: After detection of a particular group do analysis of that group. Analysis of Group .......... Test Observation C.T. for............. 1. 2. 58 Inference F. Wet test for acidic radicals: Detection of acidic radical from water solution: 1. Wet tests for CO32–, SO32–, Cl–, Br –, I– 1. O.S. + AgNO3 Distinction between halides (Cl–, Br–, I–): Note: (Perform this test only if ppt is obtained for AgNO3 which is insoluble in dil. HNO3) Test Observation Inference O.S. + Chloroform + Cl2 water in excess (shake well) Note: (If one of the halide radical is present then further analysis is not necessary. Perform confirmatory test for that detected radical.) 2. Wet test for SO42– and PO43– (This test is required to perform only, if ppt is NOT obtained in AgNO3 test) Test Observation Inference Observation Inference Observation Inference Observation Inference O.S. + Ba(NO3)2 3. WET TEST FOR NO2– Test O.S. + dil. H2SO4 + FeSO4 solution 4. WET TEST FOR NO3– Test O.S. + 3-4 drops of conc. H2SO4 + 2-3 drops of diphenyl amine 5. WET TEST FOR CH3COO Test O.S. + FeCl3 solution 59 6. WET TEST FOR C2O42– Test Observation Inference Observation Inference O.S. +dil. Acetic acid + CaCl2 C.T. for ................................ Test 1. 2. Result:- Given inoragnic salt no. 5 contains following 1. Basic radical .................................. ................ 2. Acidic radical........................................................ 3 . Molecular formula of the salt.......................................... 4. Hence the name of the salt......................................................................... Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 60 NOTES /CALCULATIONS /ROUGH WORK ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ 61 Surface Chemistry Theory: Colloid is a state of a substance (matter). A colloid is a heterogeneous system in which one substance with particle size 1 nm to 1000 nm, dispersed in another substance called dispersion medium. So colloid is not a substance but a particular state of a substance which depends on size of particles. Colloids do not pass through animal membrane of parchment paper. (Note: 1nm = 1×10-9 m = 1×10-7 cm) Colloidal system consists of two phases : a. Disperse phase : It is discontinuous phase of colloidal system having particles of colloidal size (1 nm to 1000 nm) dispersed in the dispersion medium. b. Dispersion medium : The medium in which colloidal particles are dispersed is called dispersion medium. It is a continuous phase of a colloidal system. Colloidal solutions (sols) are classified into two types : a. Lyophilic sols : In this type of colloidal solutions (sols), the disperse phase has strong affinity for the dispersion medium. These are reversible sol as the solid obtained after evaporation of liquid may be reconverted to the sol by simply shaking with the dispersion medium. Examples: Starch sol, gum sol etc. b. Lyophobic sols : In this type of colloidal solutions (sols), the disperse phase has little or no affinity for the dispersion medium. These are irreversible sol as their precipitated mass cannot be reconverted to the sol by simply shaking it with the dispersion medium. Example: Ferric hydroxide sol, Aluminum hydroxide sol etc. Date: / / Experiment No. 10 Aim: To prepare lyophilic sol (colloid) of starch. Apparatus: Two beakers (50 mL, 250 mL), glass rod, funnel, filter paper, tripod stand, wire gauze, burner, etc. Chemicals: Distilled water, soluble starch (5 g). Theory: The sols which directly formed simply by mixing substances such as starch, gum, gelatin, rubber, etc. in liquid dispersion medium (water) are called lyophilic sols. Starch form a lyophilic sol, when water is used as dispersion medium. The starch sol can be prepared by heating starch and water at about 100 0C. It is quite stable and is not affected by the presence of any electrolytic impurity. Procedure: 1. Take 5 g of starch in a 50 mL beaker and add few drops of distilled water to it and make a thin paste of starch. 2. Take 100 mL distilled water in a 250 mL beaker and heat water in a beaker till it starts boiling. 3. Pour the paste of the starch slowly with stirring into the boiling water fig. 10.1 4. Continue boiling for about 2-3 minutes and allow the beaker to cool. 5. Filter the containts of beaker through a filter paper fixed in a funnel fig. 10.2. 62 Paste of starch Glass rod Beaker Wire gauze Water Tripod stand Burner Fig. 10.1 Pouring of paste of starch in boiling water Mixture of solid and liquid Stirring rod Retort stand Funnel Clamp Filter paper traps solid Filtrate (liquid component of the mixture) Fig. 10.2 Filtration Observations: Starch forms opaque / transparent sol easily and filtered rapidly through filter paper. Conclusion: ...................................................................................................................................................... ...................................................................................................................................................... Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... 63 MCQ Select [3] or underline the most appropriate answer from given alternatives of each sub question. 1. In the lyophilic colloids affinity between the particles of dispersed phase and dispersion medium is ................ a. strong b. high c. low d. average 2. The lyophilic sol is a a. irreversible sol b. reversible sol c. hydrophobic sol d. homogeneous colloid 3. In a sol of starch, dispersion medium is ................ a. starch b. water c. ethyl alcohol d. air 4. The colloid of starch in water is ................ a. solid sol b. emulsion c. gel d. sol 5. Which of the following is NOT true about colloidal system? a. It is heterogeneous b. Aggregation of molecules or ions c. The particles are settle down under gravity d. The particles are invisible under microscope 6. Which one of the following is an example of sol? a. Butter b. Jellies c. Milk d. Gelatin in water 7. Which one of the following is an example of lyophilic sol? b. Fe(OH)3 sol c. As2S3 sol d. Starch sol a. Al(OH)3 sol Short answer questions 1. What is a sol? Ans..................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... 2. How sols are classified? Ans.................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... 3. What is lyophilic sol? Ans..................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... 4. Give two examples of lyophilic sols. Ans..................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... 5. Why lyophilic sols are called reversible sols? Ans..................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 64 NOTES /CALCULATIONS /ROUGH WORK ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ 65 Date: / / Experiment No. 11 Aim: To prepare lyophobic sol (colloid) of ferric hydroxide. Apparatus: Two beakers (250 mL), glass rod, funnel, Bunsen burner, filter paper, dropper etc. Chemicals: Distilled water, 2 % ferric chloride solution prepared by dissolving 2 g of anhydrous pure FeCl3 in 100 mL of distilled water. Theory: Sols which cannot be formed simply by mixing substances such as metals, metal hydroxides or metal sulfides etc. with liquid dispersion medium (water) are called lyophobic sols (colloids).These sols are prepared by a separate method. Ferric hydroxide is a lyophobic sol. Lyo means solvent and phobic means hating. Lyophobic sols are relatively less soluble than lyophilic sol. Ferric hydroxide sol is prepared by the hydrolysis of ferric chloride with boiling distilled water. The reaction can be shown asFeCl3(aq) 3H2O(l) boil Fe(OH)3(s) + 3HCl(aq) Procedure: 1. Take 100 mL of distilled water in a clean 250 mL beaker and heat it to boil. 2. Add 2 % of ferric chloride solution dropwise with the help of dropper to the boiling water. 3. Continue heating until deep red or brown solution of ferric hydroxide is obtained. Note: Add some water to replace the water lost by evaporation during boiling at regular intervals. 4. Keep the containt of the beaker undisturbed for some time at room temperature. 5. Filter the solution to get sol of Fe(OH)3. 2% ferric chloride solution Glass rod Beaker Wire gauze Tripod stand Burner Fig. 11.1 Pouring of 2 % FeCl3 solution in boiling water. Observation: Dark red brown sol of ferric hydroxide is formed which cannot be filtered easily through filter paper. Conclusion: ..................................................................................................................................................... .................................................................................................................................................... Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... 66 MCQ Select [3] or underline the most appropriate answer from given alternatives of each sub question. 1. In lyophobic colloid the affinity between the particles of dispersed phase and dispersion medium is ............... a. strong b. high c. low d. average 2. The name of chemical used in preparation of ferric hydroxide sol is ............... a. ferrous chloride c. ferric chloride b. iron (II) chloride d. ferric sulfate 3. In sol of ferric hydroxide the disperse phase is ............... a. FeCl3 b. Fe(OH)3 c. water d. Fe 4. The type of colloid of ferric hydroxide in water is ............... a. solid sol b. solid foam c. gel d. sol 5. Which one of the following is an example of lyophobic sol? a. Starch sol c. Gold sol b. Gelatin sol d. Gum sol 6. Which one of the following statement is INCORRECT for lyophobic sol? a. It has little affinity for the dispersion medium b. It is reversible in nature c. It is a hydrophobic sol d. It is less stable sol Short answer question 1. What is lyophobic sol (colloid)? Ans. 2. Classify the following as lyophilic sols and lyophobic sols. Gold sol, starch sol, gum sol, ferric hydroxide sol, Al(OH)3 sol. Ans 3. Why lyophobic sol is called irreversible sol? Ans Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 67 Date: / / Experiment No. 12 Aim: To study the role of emulsifying agent in stabilizing the emulsion of an oil. Apparatus: Beakers, test tube stand, test tubes, droppers, stopwatch, etc. Chemicals: Soap solution detergent solution, paraffin oil, coconut oil, groundnut oil, linseed oil, engine oil, etc. (any two oils) Theory: An emulsion is a mixture of two immiscible liquids. Emulsions prepared by shaking of two liquids. They are unstable and tends to separate into two layers on standing. In order to get a stable emulsion, addition of substance is essential called emulsifying agent or emulsifier. Soap and detergent are acts as emulsifiers. Soap and detergent are long chain compounds with polar groups. Emulsifier forms an interfacial film around the droplets of oil or water (disperse phase) and prevent the coalescence of droplets. Thus emulsion becomes stable. Procedure: Take 1 mL paraffin oil in a test tube and 1 mL groundnut oil in another test tube, then add 2 mL distilled water in each test tubes. Mark the liquid junction with marking pencil on both test tubes. Shake the mixture vigorously and put the test tubes in stands. Start the stopwatch and record the time required to separate two layers of water and oil in both the test tubes. Add two drops of soap or detergent solution with the help of dropper in each test-tube containing mixture. Shake both test-tube vigorously and place in stand and start stop watch. Record the time required for complete separation of oil and water into two layers. Observation Table: Sr. No. Emulsion Time of separation (s) I (t1) II (t2) Mean (t1+t2) 2 1 Paraffin oil + water .............. .............. .............. 2 Paraffin oil + water + soap/ detergent .............. .............. .............. 3 Groundnut oil + water .............. .............. .............. 4 Groundnut oil+ water + soap/ detergent .............. .............. .............. Conclusion: More the time consumed for separation of emulsion more will be the stability of the emulsion. Thus order of stability observed as follows. ------------------------------------------------------------------------------------------------------------------Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 68 MCQ Select [3] or underline the most appropriate answer from given alternatives of each sub question. 1. Emulsion is colloidal system in which dispersed phase and dispersion medium are ............... a. miscible liquids c. immiscible liquids b. miscible solids d. immiscible solid 2. Which of the following is NOT an emulsifier? a. Soap b. Shampoo c. Detergent d. Charcoal 3. Pick out odd emulsifier. a. Milk b. Cod liver oil c. Oil paint d. Sodium lauryl sulfate 4. By addition of emulsifying agents emulsion becomes a. more stable c. partially stable b. unstable d. highly unstable 5. There are four emulsions namely A, B, C, D take different time to separates in their different phases. B takes more time than C, C takes more time than D, and D take more time than A. Which one is more stable emulsion among the given emulsions? a. A b. B c. C d. D 6. Detergents are used as best emulsifiers because they are ............... a. non polar compound b. ionic inorganic compound c. covalent bonded organic compound d. long chain compound with polar groups. 7. Milk is ..... a. an emulsion b. a gel c. a sol d. an aerosol 8. When small quantity of an oil paint is stirred in to water, the mixture will be a ............... a. true solution c. suspension b. colloidal solution d. homogeneous solution Short answer questions 1. What is an emulsion? Ans 2. What is emulsifying agent? Ans 3. What are the types of emulsions? Ans 4. Give two examples of emulsifying agents. Ans Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 69 Date: / / Experiment No. 13 Aim: To study the shift in equilibrium between ferric ions and thiocyanate ions by changing the concentration of either of ions. Theory: Ferric chloride when dissolved in water dissociates as, FeCl3 Fe3 3Cl– 3+ Fe ions form a complex in aqueous solution as [Fe(H2O)6 ]3+. Ferric ions react with thiocyanate ion (SCN–) in aqueous solution, yielding bloodred coloration. A series of complexes are formed by Fe3+-SCN-- H2O system by the successive replacement of water molecules from [Fe(H2O)6 ]3+ complex by SCN- ion. i. [Fe(H2O)6 ]3+ + SCN– [Fe(H2O)5(SCN)]2+ + H2O ii. [Fe(H2O)6 ]3+ + 2SCN– [Fe(H2O)4(SCN)2]+ + 2H2O iii. [Fe(H2O)6 ]3+ + 3SCN– [Fe(H2O)3(SCN)3] + 3H2O These complexes have blood-red coloration. This fact is utilized in the detection of Fe3 basic radical by SCN– ion in qualitative analysis. The intensity of blood red coloration depends on number of SCN– ions in the complex. Apparatus: Burettes, Five 100 mL beakers and test tubes. Chemicals: FeCl3 (0.01M), NH4SCN (0.01M) (solutions should be provided to students), distilled water. Reaction: [Fe (H2O)6]3+ + 6SCN[Fe (SCN)6]3– + 6H2O Procedure: 1. Mix FeCl3 (0.01M), NH4SCN (0.01M) and distilled water in five different 100 ml beakers in volumes as shown in the following table. Beaker 0.01M FeCl3 mL 0.01M NH4SCN mL Distilled water mL Intensity of color I 5.0 15.0 5.0 ................. II 5.0 10.0 10.0 ................. III 5.0 5.0 15.0 ................. IV 7.5 15.0 2.5 ................. V 2.5 15.0 7.5 ................. 2. Mix the solution well in every beaker and transfer it to five different test tubes. 3. Compare the colors developed in five different test tubes. Conclusion: The balanced chemical reaction suggest that for obtaining better yield of the product [Fe(SCN)6 ]3– (blood red coloration), reactant concentration of FeCl3 and NH4SCN is in ratio 1:3. Therefore the intensity of color in beaker I is the ideal. Note: 0.01M FeCl3 and 0.01M NH4SCN. Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... 70 MCQ Select [3] or underline the most appropriate answer from given alternatives of each sub question. 1. Which color obtained when 0.01M FeCl3 solution is mixed with 0.01M NH4SCN solution? a. Bluish green b. Blood-red c. Violet d. Yellow 2. What is the ratio of reactant concentration of FeCl3 and NH4SCN to give better yield of the [Fe(SCN)6]3–? a. 1:1 b. 1:3 c. 3:1 d. 1:2 3. What is the total volume of 0.01M FeCl3, 0.01M NH4SCN and distilled water in each beaker? a. 10 b. 15 c. 20 d. 25 Short answer questions 1. What is chemical equilibrium? Ans 2. Which color obtained, when [Fe(H2O)6]3+ treated with NH4SCN? Ans 3. What is the ratio of concentrated NH4SCN and [Fe(H2O)6]3+ is taken for better yield of [Fe(SCN)6]3– ? Ans 4. What is the effect of catalyst on chemical equilibrium? Ans 5. Chemical equilibrium is dynamic in nature. Justify your answer. Ans 6. Does law of mass action apply on the following reaction? [Fe(H2O)6]3+ + 3SCN– o [Fe(SCN)6]3– + 3H2O Ans 7. How does concentration of reactant affect direction of chemical equilibrium? Ans Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 71 Date: / / Experiment No. 14 Aim: To study the shift in equilibrium between hexaaquacobalt (II) ion [Co(H2O)6]2+ and chloride ions (Cl-) by changing the concentration of either of the ions. Theory: When CoCl2 is dissolved in water it ionizes as follows. CoCl2 Co2+ + 2Cl– Ionized Co2+ ions form a complex [Co(H2O)6 ]2+ ion with water. H 2O H 2O Co2+ +6 H2O OH2 CO OH2 2+ OH2 H2O OH2 i.e. H2O OH2 CO OH2 2+ OH2 OH2 The complex in presence of Cl– ions forms [Co(H2O)6]Cl2 and the color of this complex is pink. The intensity of the color depends on the concentration of the complex. The equation can be displayed by changing the concentrations of [Co(H2O)6]2+ and Cl– ions. In general increase in concentration of reactants shifts the equilibrium in the direction of products and vice versa. Apparatus: Burette Five 100 mL beakers, test tube, test tube stand Chemicals: CoCl2 (0.1M), HCl (0.1M) (solutions should be provided to students), distilled water Reaction: [Co(H2O)6]2+ + 2 Cl– [Co(H2O)6]Cl2 Procedure: 1. Mix CoCl2 (0.1M), HCl (0.1M) and distilled water in five different 100 ml beakers in volumes as shown in the following table. Beaker 0.1M CoCl2 mL 0.1M HCl mL Distilled water mL I 10.0 20.0 10.0 II 10.0 30.0 0.0 III 10.0 10.0 20.0 IV 15.0 20.0 5.0 V 5.0 20.0 15.0 Intensity of color 2. Mix well solutions of every beaker and transfer it to five different test tubes. 3. Compare the colors developed in five different test tubes. Conclusion: The balanced chemical equation suggests that for obtaining better yield of the product [Co(H2O)6]Cl2 (pink color) reactant concentration of CoCl2 and HCl in the ratio 1:2. Therefore the intensity of color in beaker I is the ideal. The intensity of color in beaker II and IV will increase indicating in concentration of product. Whereas in beaker III and IV will decrease indicating decrease in concentration of product. Remark and sign of teacher: ................................................................................................. ...................................................................................................................................................... 72 MCQ Select [3] or underline the most appropriate answer from given alternatives of each sub question. 1. The total volume of 0.1M CoCl2, 0.1M HCl and distilled water in each beaker is a. 10 mL b. 20 mL c. 30 mL d. 40 mL 2. The color of solution of mixture of 0.1M CoCl2 and 0.1M HCl is ....... a. Red b. Pink c. Blue d. Yellow 3. What is the ratio of reactant concentration of CoCl2 and HCl for obtaining better yield? a. 1:1 b. 1:2 c. 2:1 d. 1:3 4. In which one of the beaker the intensity of color is an ideal? a. I b. II c. III d. IV Short answer questions 1. What is chemical equilibrium? Ans 2. Which color obtained when [Co(H2O)6]2+ treated with HCl? Ans 3. What is ratio of concentration of (0.1M) HCl and (0.1 M) CoCl2 is taken for better yield of [Co(H2O)6]Cl2? Ans 4. What is effect of catalyst on chemical equilibrium? Ans 5. Chemical equilibrium is dynamic in nature. Justify your answer. Ans 6. Does law of mas action apply on the following reaction [Co(H2O)6]2+ + 2 Cl– [Co(H2O)6]Cl2? Ans 7. How does the concentration of reactant affect direction of chemical equilibrium? Ans Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 73 Date: / / Experiment No. 15 Aim: To study the pH change in the titration of strong base (0.1M NaOH) and strong acid (0.1M HCl) using universal indicator. Apparatus: Burette, pipette, conical fl ask, beakers, burette stand, funnel, beakers, etc. Chemicals: 0.1M HCl, 0.1M NaOH, universal indicator. Theory: The solution of strong base NaOH, due to higher concentration of OH- ions has higher pH. As HCl is added to the NaOH solution, the pH of the solution decreases which changes the color of universal indicator which has a wide range of pH from 0 to 14 Procedure: 1. Wash the burette, pipette and conical fl ask with water. 2. Rinse the burette with 0.1M HCl solution and fill it with HCl solution after removing air bubble from nozzle and adjust lower meniscus of solution at zero mark. 3. Rinse the pipette with 0.1M NaOH solution and pipette out 10 mL of NaOH and transfer in the conical fl ask. 4. Add 2 to 3 drops of universal indicator into the solution in conical fl ask, shake well, observe the violet color of solution and record the pH of the solution. 5. Add a drop of 0.1M HCl solution from the burette in conical fl ask till the color of the solution changes to indigo color. Note the burette reading. 6. Continue addition of 0.1M HCl solution from the burette dropwise, till the color of the solution changes to blue, then green, yellow, orange and finally red which indicates changes in pH of solution. 7. Note down the burette readings corresponding to each color change. 8. Don’t fill the burette with HCl solution till color changes from indigo to red. Observation: 1. Solution in burette : ................................ 2. Solution in conical fl ask : ...................... 3. Indicator : ............................ Observation Table: Sr. No. 1 Color of solution Indigo 2 Blue 3 Green 4 Yellow 5 Orange 6 Red Volume of 0.1M HCl from burette in mL pH Nature Conclusion: The pH of the solution goes on decreasing on addition of 0.1M HCl from the burette. The different concentration of H+ ions gives different colors with universal indicator. Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 74 MCQ Select [3] or underline the most appropriate answer from given alternatives of each sub question. 1. In the titration of strong base 0.1M NaOH aginst 0.1M HCl solution, using universal indicator, the color of the solution changes to blue then pH of the solution is a. zero b. 4 c. 7 d. 8 2. In the titration of strong base (0.1M NaOH) aginst 0.1M HCl solution, using universal indicator, the pH of the solution change to 6 then the color of the solution in the fl ask becomes ........... a. blue b. yellow c. orange base d. green 3. In the titration of strong base 0.1M NaOH aginst 0.1M HCl solution, using universal indicator the pH of the solution (in the conical fl ask) becomes 1, the nature of fl ask solution is ........... a. strongly acidic b. strongly basic c. weekly acidic d. neutral 4. In the titration of strong base 0.1M NaOH aginst 0.1M HCl solution, using universal indicators, the color of the fl ask solution becomes green, what is the burette reading of HCl solution? a. 10 mL b. 8 mL c. 12 mL d. 6 mL 5. In the titration of strong base 0.1M NaOH aginst 0.1M HCl solution, using universal indicator, the color of the solution in the fl ask becomes blue the nature of fl ask solution is a. strongly acidic b. strongly basic c. weakly basic d. neutral 6. What is the color of the solution in conical fl ask, when 10 mL of 0.1M NaOH is neutralized by 0.1M HCl solution? a. Blue b. Green c. Yellow d. Orange Short answer questions 1. Why is in given experiment color of the solution changes? Ans 2. What is color of universal indicator in strong acidic and strong basic medium? Ans 3. What is change in pH of the 0.1M NaOH while adding 0.1M HCl from the burette? Ans 4. Why universal indicator is better than litmus paper? Ans 5. If the color of universal indicator changes from green to yellow, predict the change in pH. Ans Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 75 Date: / / Experiment No. 16 Aim: To determine the pH and nature of salt solution (NH4Cl, Na2CO3, CH3COONa, NaCl) using pH paper or Universal indicator Apparatus: Five Test tubes, dropper, test tube stand, etc. Chemicals: 1 gram of each salt NH4Cl, Na2CO3, CH3COONa and NaCl Theory: Salts when dissolved in water, undergo hydrolysis and produce acidity, alkalinity (basicity) or neutrality in the solution, depending upon the nature of the salts. NH4Cl + H2O NH4OH + HCl (Acidic) Na2CO3 + 2H2O 2 NaOH + H2CO3 (Basic) CH3COONa + H2O CH3COOH + NaOH (Basic) NaCl + H2O NaOH + HCl (Neutral) Procedure: 1. Dissolve 1 gm of each salt in 10 mL of distilled water in four different clean test tubes marked A, B, C and D. 2. Add two to three drops of Universal indicator or dip one small strip of pH paper in each of the test tubes marked A, B, C and D. 3. Observe the color developed in the solution or pH paper strips and note the corresponding pH values. (Take one unknown salt and prepare its solution and find out its pH) Yellow Observation and result table: Test Tube A Red Green Fig. 16.1 Color of salts Salt solution Color of pH paper/color of solution NH4Cl B Na2CO3 C CH3COONa D NaCl E Unknown Blue pH of solution Nature of solution Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 76 MCQ Select [3] or underline the most appropriate answer from given alternatives of each sub question. 1. The pH of aqueous solution of NH4Cl salt is a. ! 7 c. 7 b. equal to 7 d. between 7 to 14 2. The nature of aqueous solution of CH3COONa is a. basic c. neutral b. acidic d. amphoteric 3. The pH of aqueous solution of NaCl is a. 7 c. 7 b. ! 7 d. zero 4. When pH paper is dipped in the aqueous solution of Na2CO3 the pH paper develop ----- color. a. yellow c. blue b. green d. orange 5. The nature of aqueous solution of Na2CO3 a. basic c. neutral b. acidic d. amphoteric 6. When a strip of pH paper is dipped in aqueous solution of NH4Cl the pH paper develops-----color. a. yellow c. blue b. green d. red 7. Which of the following salt does not undergo hydrolysis? a. NH4Cl c. Na2CO3 b. KCl d. CH3COONa Short answer questions 1. Write chemical reaction for the hydrolysis of a salt of weak acid and strong base. Ans 2. Write name and chemical formula of a salt of strong acid and strong base. Ans 3. When water is added in NaCl, it will undergo hydrolysis or not? Why? Ans Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 77 Date: / / Experiment No. 17 Aim: To determine melting point of given organic compound. Apparatus: Thiele’s tube, retort stand with clamps thermometer, capillary tube, thread, burner etc. Chemicals: Given organic compound, liquid paraffin Theory: A pure organic compound possesses characteristic physical properties such as refractive index, specific gravity, melting point, boiling point etc. However for practical purpose in laboratory melting point and boiling point are used as criteria for purity. A pure organic solid has a definite and sharp melting point, while an impure substance has a lower and indefinite melting point. The melting point of a substance is the temperature at which the solid and liquid phases exist in equilibrium with each other. Procedure: Take a small capillary tube and seal it at one end by heating. Fill the finely powdered dry organic compound (about 1 cm in height) in the capillary tube by tapping it on porcelain tile. Tie the capillary tube to the thermometer such that bulb of thermometer and organic substance are at the some level. Now, suspend the thermometer in Thiele’s tube containing liquid paraffin such that it should not touch the sides of the Thiele’s tube. Heat gently the side arm only with wavy fl ame. Stop heating Thieles tube when solid starts melting. Record the temperature when solid is completely melts. This temperature is melting point of given organic compound. Observation: Melting point of given compound = -------- 0C = (-------- 0C+ 273) K = -------- K Table: Melting point of some organic compounds Sr. No. Compounds Melting Point (0C) 1 Naphthalene 80 2 Oxalic acid 101 3 E-naphthol 122 4 Benzoic acid 122 Fig. 17.1 Determination of melting point Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 78 MCQ Select [3] or underline the most appropriate answer from given alternatives of each sub question. 1. Melting point of a solid is a. The temperature at which a solid is in equilibrium with its liquid, at 1atm pressure. b. The temperature at which a liquid is in equilibrium with its gas, at 1atm pressure. c. The temperature at which the vapor pressure of the liquid is equal to atmospheric pressure. d. The temperature at which solid in capillary tube start melting 2. In the determination of melting point of a solid, the solid in small quantity is filled in a ....... a. fusion tube b. capillary tube with one sealed end. c. Thiele’s tube containing paraffin liquid. d. capillary tube with both open end. 3. Melting point is a criteria of purify of a organic solid because a. a pure liquid boil sharply at a definite temperature. b. a pure solid melts sharply at a definite temperature. c. a pure solid melts at some higher temperature than its melting point. d. a pure liquid boils at some lower temperature than its boiling point 4. The melting point of oxalic acid is a. 80 0C b. 101 0C c. 110 0C d. 122 0C 5. In the determination of melting point, Thiele’s tube is filled with paraffin oil because a. paraffin oil has high boiling point b. paraffin oil is chemically highly reactive c. paraffin oil undergo decomposition d. paraffin oil react solid quickly. 6. The temperature in 0C is converted into Kelvin by addition of a. 0 b. 100 c. 273 d. 373 Short answer questions 1. Define melting point. Ans 2. What is criteria of purity of solid substances? Ans. Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 79 Date: / / Experiment No. 18 Aim: To determine the boiling point of an organic compound. Apparatus: Thiele’s tube, retort stand with clamps thermometer, capillary tube, fusion tube, thread, burner, etc. Chemicals: Given organic liquid compound, liquid paraffin. Theory: Boiling point of a liquid, is the temperature at which vapor pressure of a liquid is equal to the external atmospheric pressure. (Boiling point changes with change in external pressure.) Procedure: 1. Fill small quantity of given organic liquid in a fusion tube. 2. Take a capillary tube seal its one end by mean of heating and place it in a fusion tube inverted (sealed end upward and open end dipped in the liquid.) 3. Tie the fusion tube near the bulb of the thermometer by thread. 4. Now, suspend the thermometer tied with fusion tube in Thiele’s tube containing liquid paraffin such that it should not touch the sides of the Thiele’s tube and organic liquid in fusion tube should be completely dipped in paraffin. Precaution should be taken such that paraffin should not be enterd in fusion tube. 5. Heat gently the side arm with waving fl ame. 6. Stop the heating, when bubbles start coming out from the open end of the capillary tube. 7. Record the temperature when continues bubbling in fusion tube is stop and liquid rises in the capillary. Fig. 18.1 Determination of boiling point Observation: Boiling point of given organic compound = ------- 0C = (...........0C+ 273) K = ------ K Note: Minimum two different oraginc liquid compounds should be taken for this experiment. Table: Sr. No. 1 2 Compounds Acetone Acetic acid Boiling Point (0C) 56 118 3 4 Aniline Ethyl alcohol 184 78 80 MCQ Select [3] or underline the most appropriate answer from given alternatives of each sub question. 1. The boiling point of a liquid is the temperature at which a. vapor pressure of liquid is higher than external pressure b. vapor pressure of liquid is lower than external pressure c. vapor pressure of liquid is equal to the external pressure d. the external pressure is equal to atmospheric pressure 2. The boiling point of acetone in Kelvin is ------a. 273 K c. 329 K b. 356 K d. 423 K 3. Which of the following apparatus is use for the determination of temperature? a. Thermometer c. Speedometer b. Barometer d. Colorimeter 4. In which of the following stage, boiling point of organic liquid is to be recorded? a. At the time of heating Thiele’s tube b. Continuous stream of bubbles start coming c. Last bubble is given out and liquid raise in capillary d. When first bubble comes out of capillary Short answer questions 1. Define the term boiling point. Ans 2. What is criteria of purity of liquid substances? Ans 3. Draw neat label diagram of determination of boiling point of liquid. Ans: Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 81 Experiment No. 19 Date: / / Aim: To prepare pure crystals of copper sulfate (CuSO4.5H2O) or benzoic acid C6H5-COOH from a given impure sample. Theory: Generally the substance is more soluble at higher temperature in a given solvent. In chemistry, recrystallization is a technique use to purify chemicals. By dissolving both impurities and a compound in an appropriate solvent, either the desired compound or impurities can be removed from the solution, leaving the other behind with filter paper. Apparatus: Glass beakers, glass rod, funnel, filter paper, evaporating dish, wire gauze, tripod stand, Bunsen burner, etc. Procedure: 1. 5 gm of an impure sample of copper sulfate or benzoic acid is dissolved at high temperature in minimum quantity of water. 2. The solution is heated to get the saturated solution. This hot solution is filtered to remove insoluble impurities, evaporate this solution in evaporating dish. 3. The filtrate is allowed to cool slowly to room temperature when fine crystals of pure substance are formed. 4. These crystals are removed from the mother liquor by filtration and washed with the same solvent to remove adhered impurities. Theses crystals are then dried. Step1 Step2 evaporating dish solvent impure solid stir to dissolve solid The solution is heated to evaporate most of the solvent Fig. 19.1 Simple crystallization process. Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... 82 MCQ Select [3] or underline the most appropriate answer from given alternatives of each sub question. 1. At which temperature generally the substance is more soluble in a given solvent? a. Very very low c. Very low b. At room temperature d. Higher temperature. 2. The stage at which crystal starts to appear on glass rod is called ----------. a. boiling point c. melting point b. point of crystallization d. triple point 3. Which solution is to be prepared for crystallization? a. Unsaturated c. Supersaturated b. Saturated d. Fused mass of impure substance 4. What is the Color of prismatic copper sulfate crystals? a. Red b. Blue c. Pink d. Green 5. What is the Color of crystals of benzoic acid? a. Black b. Yellow c. White d. Brown Short answer questions 1. How does cooling rate affect crystal size? Ans. 2. Which type of solvent is used for crystallization? Ans 3. Write the names of observed Color of saturated solutions of copper sulfate and benzoic acid in water at high temperature. Ans 4. Write the names of apparatus used during filtration process. Ans 5. What is filtrate? Ans 6. Arrange the following steps involved in crystallization in proper sequence. a. Filtration b. Dissolution c. Drying d. Crystallization e. Solvent selection. Ans Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 83 Date: / / Activity 1 Aim: To prepare 100 mL of 0.1 M standard solution of oxalic acid. Theory: The molecular formula of oxalic acid is H C O .2H O. Its molar mass is 126 g/mol. 2 2 4 2 1000 mL of 1M solution of oxalic acid contains 126 g of H2C2O4.2H2O Hence 100 mL of0solution of oxalic acid will contains 100 mL u0u126 g = = 1.26 g of oxalic acid. 1000 mL u0 Apparatus: 100 mL volumetric fl ask, beaker, glass rod etc. Chemicals: Oxalic acid, distilled water. Procedure: 1. Wight accurately 1.26 g of oxalic acid. Transfer it to a beaker and add little distilled water. Stir it well with the help of glass rod. 2. Transfer the solution from beaker to volumetric fl ask, using conical funnel and glass rod properly (Take care to prevent loss of even a single drop of solution). 3. Wash the beaker twice / thrice with distilled water and transfer the washing to the volumetric fl ask. 4. Dilute the solution by adding distilled water up to the mark on the volumetric fl ask to make the volume 100 mL. (See that the volume marking appears tangential to the meniscus of the final solution) Fig. Activity 1.1 Volumetric flask. Conclusion: -------------------------------------------------------------------------------------------------Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 84 MCQ Select [3] or underline the most appropriate answer from given alternatives of each sub question. 1. A solution whose concentration is accurately known is called----a. dilute solution b. concentrated solution c. standard solution d. colloidal solution 2. The molar mass of oxalic acid is a. 126 u b. 126 g / mol c. 12.6 u d. 12.6 g / mol 3. To prepare standard 1M solution of oxalic acid. a. 0.126 g of oxalic acid is dissolved in 1 L of solution. b. 1.26 g of oxalic acid is dissolved in 1 L of solution. c. 12.6 g of oxalic acid is dissolved in 1 L of solution. d. 126 g of oxalic acid is dissolved in 1 L of solution. 4. To prepare 100 mL of standard 0.1M oxalic acid solution. a. 0.63 g of oxalic acid is dissolved in 100 ml of distilled water. b. 1.26 g of oxalic acid is dissolved in 100 ml of distilled water. c. 12.6 g of oxalic acid is dissolved in 1000 ml of distilled water. d. 126 g of oxalic acid is dissolved in 100 ml of distilled water Short answer questions 1. Calculate the amount of oxalic acid required to prepare 1000 mL 0.1 M standard solution of oxalic acid Ans. . 2. Calculate the molar mass of oxalic acid. (C = 12, O = 16, H = 1) Ans. Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 85 Date: / / Activity 2 Aim: To determine pH of different fruit juices by using universal indicator or pH paper. Apparatus: Test tubes, droppers, glass rod, beakers, etc. Chemicals: Different fruit juices, pH paper or universal indicator. Procedure: 1. Take 5 ml of given different fruit juices in separate A, B, C, D marked test tubes. 2. Put pH paper or add 2 drops of universal indicator in each test tube and shake it well. 3. Observe the color of pH paper or solution developed in each test tube. 4. Determine the pH of each solution by comparing the colors with the standard pH color strips. 5. Find out nature of given fruit juices on the basis of pH values. Acidic Neutral Red Orange Yellow Green Alkaline Blue Indigo Violet Fig. Activity 2.1 pH scale Observation table and Conclusion : Sr. No. Juice sample Color of pH paper or solution of universal indicator pH Nature 1 ....................(A) ................................................ .......... ............. 2 ....................(B) ................................................ .......... ............. 3 ....................(C) ............................................... .......... ............. 4 .....................(D) ............................................... ........... ............. Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 86 MCQ Select [3] or underline the most appropriate answer from given alternatives of each sub question. 1. In a 5 mL solution of lemon juice add 2 drops of universal indicator, the color of solution becomes red-orange, the pH of solution is ............... a. ! 7 c. equal to 7 b. 7 d. between 7 to 14 2. The pH of grape juice is about 3.3, the nature of grape juice is ............... a. Acidic c. neutral b. alkaline d. acidic as well as alkaline 3. When a strip of pH paper is dipped in a solution of orange juice, the color of pH paper become orange the pH of solution is ............... a. ! 7 c. equal to 7 b. 7 d. between 7 to 14 Short answer questions 1. What is the pH of pure water? Ans 2. On mixing any two fruit juices, would pH remains same or differ? Verify your answer experimentally. Ans 3. What is the pH range of universal indicator? Ans Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 87 Date: / / Activity 3 Aim: Calibration of pipette by burette. Apparatus: Burette (25 mL), pipette (10 mL), beaker (100 mL), etc. Chemicals: Distilled water Procedure: 1. Take a 25 mL burette and fixed it on burette stand. 2. Fill the burette with distilled water upto10 mL mark with lower meniscus. 3. Now pipette out 10 mL of distilled water and add it to the burette. 4. Observe the level of water in the burette, if it is zero then that pipette is calibrated. 5. If the level of the water in the burette is not zero or more than zero, then take another pipette for calibration. 6. Continue this process till pipette is calibrated. Pipette Stopcock Fig. Activity 3.1 (a) Burette (25 mL capacity) Fig. Activity 3.1 (b) Pipette (10 mL capacity) Conclusion: The pipette is ----------------------------------------------------------------------------------. Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 88 MCQ Select [3] or underline the most appropriate answer from given alternatives of each sub question. 1. The minimum volume of solution is measured by burette is a. 0.01 mL c. 1.0 mL b. 0.1 mL d. 10.0 mL 2. The capacity of pipette used by you in this activity is ............... a. 0.01 L c. 1 L b. 0.1 L d. 10 L 3. The Least count of the burette is ............... a. 1 mL c. 0.01 mL b. 0.1 mL d. 0.001 mL 4. A student added 10 mL distilled water in burette already having 5 mL of distilled water by calibrated pipette. What is correct burette reading in burette? a. 5 mL c. 15 mL b. 10 mL d. 25 mL Short answer questions 1. Arrange the following step in proper sequence a. Burette fix on a burette stand b. Observed the level of water in burette c. Take 25 mL burette d. Take 10 mL of distilled water by pipette e. Add 10 mL water from pipette to the burette f. Fill the burette upto 10 mL with water Ans . Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 89 Date: / / Activity 4 Aim: To obtain pure water from impure water containing ink by simple distillation method. Apparatus: Distilling fl ask, water condenser, thermometer, retort stand with clamps, Bunsen burner, a receiver (fl ask), etc. Chemical: Impure water containing ink. Theory: Distillation method is generally used to purify a volatile liquid from a non volatile substance dissolved in it, or from a liquids which are less readily volatile than the liquid to be purified. A pure liquid under constant pressure boils at a constant temperature and hence distillation of a liquid forms a method of purifying it. This method is useful however only when the liquid does not decompose on boiling. The method consists of heating the liquid substance in a fl ask known as the distilling fl ask (fig. 4.1). The fl ask is heated directly on a wire gauze by a Bunsen burner or indirectly in a water/ oil bath. The liquid boils and forms vapors, leaving behind the impurities in the distilling fl ask. The vapors of the liquid is then cooled in a water condenser, where it condenses to reproduce the liquid in a pure form. The liquid collects is a fl ask known as the receiver. The distilling fl ask is normally a round bottom fl ask with a side tube (arm). A cork carrying a thermometer through it is fitted to the distilling fl ask so that the bulb of the thermometer is in level with the side tube. The side tube is connected to the water condenser by another cork (adapter). Cold water is circulated through the condenser in a direction opposite to the fl ow of the vapor of the liquid substance. This cold water keeps the condenser cool and provides a cool surface for the vapors to condense. The temperature at which vapors start to condense in liquid and remains constant, is nothing but the boiling point of water. This temperature in the thermometer remains constant till all distillate will collect into receiver. Thermometer Condenser Clamp Retort stand Vapors Distilling Flask water out Burner cold water in Receiving Flask Distillate Fig. Activity 4.1 Simple distillation Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 90 Procedure: 1. Pour impure water containing ink into the distilling fl ask by means of a funnel with a long stem. Seal the mouth of the distilling fl ask with rubber cork having a hole at the center in which thermometer is fitted. Add some pieces of porcelain to avoid bumping. 2. Now heat the fl ask carefully by means of a Bunsen burner. The solution begins to boil after some time. 3. The water vapors formed passes into the condenser through the side tube of the distilling fl ask. 4. The vapors are cooled and condensed to drops of water which collect into the receiver. 5. The pure water obtained is distilled water (distillate) having no ink contain. 6. Impurities (ink) remains behind in distilling fl ask. Conclusion/ Result: The pure water is obtained from the impure water. MCQ Select [3] or underline the most appropriate answer from given alternatives of each sub question. 1. The boiling point of pure water is .............. a. 100 K b. 273 K c. 373 K d. 273 0C 2. Impure organic liquid having soluble impurities can be purified by a .............. a. crystallization c. simple distillation b. fractional crystallization d. fractional distillation 3. Which of the following statement is correct about simple distillation .............. a. process to convert impure liquid into pure form. b. process to convert pure liquid into impure liquid. c. process to convert impure solid in pure form. d. process to separate mixture of two different impure liquid. Short answer questions 1. Define simple distillation method? Ans 2. What is the role of water condenser in simple distillation method? Ans 3. What is the role of bumping stone in simple distillation method? Ans Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 91 Date: / / Activity 5 Aim: To detect the presence of adulterant in given food samples. Theory: The substance which lowers or degrades the quality of food material is called adulterant. Sr. No. Name of food material Common Adulterant 1 Powdered Sugar Baking soda 2 Turmeric powder Metanil yellow color 3 Tea powder Exhausted tea leaves dried and artificially Colored 4 Chili powder Brick powder 5 Edible oil Argemone oil Chemicals: Given food samples, dil. HCl, conc. HCl, etc. Apparatus: Test tubes, test tube stand, etc. Procedure: Sr. Name of Test Observation No. Food 1 Powdered Sample of sugar + Effervescence sugar dil. HCl No effervescence 2 3 4 5 Turmeric powder Tea powder Chili powder Edible oil Sample of turmeric powder + few drops of conc. HCl Sprinkle the sample of tea powder on a wet filter paper Violet color No violet color Yellow or red colored spot appears Inference Sugar sample is adulterated Sugar sample is not adulterated / Pure Turmeric powder sample is adulterated Turmeric powder sample is not adulterated / Pure Tea sample is adulterated No yellow or red spot appears Tea sample is not adulterated / Pure Sprinkle chili powder on the surface of water Brick powder settled at the bottom of test tube No brick powder settled at the bottom of test tube Chili powder sample is adulterated 5 ml sample of edible oil + 5 ml of conc. HCl and shake. Yellow or orange yellow color appears in lower acid layer Edible oil sample is adulterated Chili powder sample is not adulterated / Pure Edible oil sample is No yellow or orange yellow color appears in not adulterated / Pure lower acid layer 92 Conclusion: The given food materialsSr. No. Name of food material 1 Powdered sugar 2 Turmeric powder 3 Chili powder 4 Tea powder 5 Edible oil Pure / adulterated MCQ Select [3] or underline the most appropriate answer from given alternatives of each sub question. 1. Turmeric powder is adulterated with ……….............color. a. yellow c. saffron b. metanil yellow d. indigo red 2. When a small quantity of dil. HCl is added to a sample of powdered sugar effervescence of CO2 are observed. The sugar sample is ………......... a. adulterated with brick powder b. not adulterated (Pure) c. adulterated with baking soda d. adulterated by metanil yellow 3. Now a days chili powder is adulterated with ………......... a. saw dust c. brick powder b. red color d. yellow color 4. When 5 mL of concentrated HCl is added to 5 mL sample of edible oil, lower layer of acid becomes yellow, orange yellow or crimson colored indicates. a. edible oil sample is pure. b. eible oil sample is adulterated with conc. nitric acid. c. edible oil sample is adulterated with argemone oil. d. edible oil sample is adulterated with conc. sulphuric acid? Short answer questions Q1. What do you meant by adulteration in food materials? Ans Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 93 Date: Activity 6 / / Aim: To determine pH of HCl solution of various concentrations by using pH paper or universal indicator. Apparatus: Test tubes, test tube stand. Chemicals: 0.1M, 0.01M, 0.001M HCl solution, pH paper or universal indicator. Theory: pH = -log10[H+] For Acidic solution, pH 7, Basic solution pH ! 7,and neutral solution pH = 7. The value of pH changes with change in concentration of HCl. Procedure: 1. Take 5 ml each of 0.1 M, 0.01 M, 0.001 M HCl solutions in separate test tubes marked A, B, C. 2. Add 2 drops of universal indicator in each test tube or put piece of pH paper in each test tube. 3. Observe the Color of solution or pH paper and record pH of each solution. Acidic Neutral Alkaline Red Orange Yellow Green Blue Indigo Violet Fig. Activity 6.1 pH range Note: Student has to prepare 0.01M and 0.001M HCl solution from the given 0.1M HCl solution. Observation Table/ Conclusion: Sr. No. Solutions Concentration of solutions Color of pH paper or solution pH 1 A ........................ ........................ ............. 2 B ........................ ........................ ............. 3 C ........................ ........................ ............. Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 94 MCQ Select [3] or underline the most appropriate answer from given alternatives of each sub question. 1. If nature of the solution is acidic, then its pH value is --a. ! 7 c. equal to 7 b. 7 d. in between 7 to 14 2. Which of the following indicator have different pH range is -a. phenolphthalein indicator c. methyl orange indicator b. acid-base indicator d. universal indicator + 3. The negative log of H ions concentration to the base 10, is known as --a. pH c. pKa b. pOH d. pKb 4. The Color of universal indicator in strongly acidic solution is ---a. red c. oranges b. violet d. blue + 5. If concentration of H ions increase, the values of the pH of the solution will be ----a. decrease c. increase b. remain constant d. first increases then decreases Short answer questions Q1. What do you meant by pH of the solution? Ans Q2. If the concentration of given solution of HCl is 0.01M. Calculate the pH of the solution. Ans..................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 95 Date: / / Activity 7 Aim: To determine pH of NaOH solution of various concentrations by using pH paper or universal indicator. Apparatus: Test tubes, test tube stand. Chemicals: 0.1 M NaOH, 0.01 M NaOH, 0.001 M NaOH solutions, pH paper or universal indicator. Theory: pOH = -log10[OH-]; pH = 14- pOH For Acidic solution pH 7, Basic solution pH ! 7, Neutral solution pH = 7. The value of pH changes with change in concentration of NaOH. Procedure: 1. Take 5 ml each of 0.1M, 0.01M, 0.001M NaOH solutions in separate test tubes marked A, B, C. 2. Add 2 drops of universal indicator in each test tube or put piece of pH paper in each test tube. 3. Observe the Colors of solution or pH paper and record pH of each solution. Acidic Neutral Red Orange Yellow Alkaline Green Blue Indigo Violet Fig. Activity 7.1 pH range Note: Student has to prepare 0.01M and 0.001M NAOH from the given 0.1M NaOH solution. Observation Table/ Conclusion: Sr. No. 1 Solutions A Concentration of solutions ........................ Color of pH paper or solution ............................ pH ............. 2 B ........................ ............................ ............. 3 C ........................ ............................ ............. Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 96 MCQ Select [3] or underline the most appropriate answer from given alternatives of each sub question. 1. If nature of the solution is alkaline is then its pH values is ....... a. ! 7 c. Equal to 7 b. 7 d. In between 7 to 14 2. Which of the following indicator have different pH range is ....... a. Phenolphthalein indicator c. Methyl orange indicator b. Acid-base indicator d. Universal indicator 3. The negative logarithm to the base 10 of OH- ions concentration is known as ....... a. pH c. pKa b. pOH d. pKb 4. The color of universal indicator in strongly basic solution is ....... a. red c. orange b. violet d. blue 3. If concentration of OH- ions increase, the values of the pH of the solution will be ....... a. decrease c. increase b. remain constant d. first increases then decreases Short answer questions 1. What is pOH of the solution? Ans 2. If the concentration of given solution of KOH is 0.01M. Calculate the pOH and pH of the solution. Ans Remark and sign of teacher: .................................................................................................. ...................................................................................................................................................... ...................................................................................................................................................... 97 NOTES /CALCULATIONS /ROUGH WORK ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ 98 NOTES /CALCULATIONS /ROUGH WORK ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ 99 NOTES /CALCULATIONS /ROUGH WORK ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ........................................................................................................................................................... ............................................................................................................................................................ 100 101 102 103 104 105 106 Exam. Seat No. Roll No. Maharashtra State Bureau of Textbook Production and Curriculum Research, Pune-04 Certificate Laboratory journal for Chemistry This is to certify that Shri/Miss ....................................................................... has satisfactory carried out the required practical work prescribed by Maharashtra State Bureau of Textbook Production and Curriculum Research, Pune-04 for first year jr. college science course Roll No. ------------ in subject Chemistry and that this journal his/her bonafide work in year 20... - 20 ... . No of experements performed Subject Teacher No of activities performed Examiner Stamp 107 Principal 108 CHEMISTRY PRACTICAL NOTEBOOK STANDARD XI (agm`Zemó àmË`{jH$ Zm|Xdhr B`Îmm 11 dr) < 59.00