LAB. 1
Practical organic chemistry
LABORATORY RULES AND SAFETY PRECAUTIONS
Safety!
To avoid that, follow instructions:
1-Always wear safety eye glasses when in the laboratory.
2-Beware of hot glass, Watch for small chips and
cracks on glassware.
3-All books, coats, and other personal effects should remain
separate from the experiment area.
4-Do not touch, taste, or smell chemicals unless directed to do so.
5-Read labels carefully, don't use chemicals with no labels.
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6-pour acids slowly and carefully, Never add water to acids.
7-Wear gloves when handling caustic chemicals.
8-When inserting glass tubing or thermometers into rubber stoppers, always
lubricate both the glass tubing and the hole with glycerin.
9- To determine the odor of a compound, bring the stopper of the bottle
cautiously towards the nose, do not inhale.
10- Never, heat an organic liquid directly over a flame except under a
condenser. When refluxing a liquid, be sure that the condenser is tightly fitted.
If a temperature below 95 oC is sufficient, use a steam bath rather than a
burner.
COMMON LABORATORY GLASS WARE AND EQUIPMENT
Beaker
Glass rod
Funnels
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Conical
Separation Funnel
Test Tube Holder
Bunsen Burner
Spatula
Test tubes
RackRound
Volumetric Flask
Bottomed Flask Graduated Cylinder
Water Bath
Hot Plate
Identification of Organic compounds
Physical character :
• odour .
• Color.
• Condition.
• Solubility and miscibility.
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Balance
Physical Properties:
1-Condition:
Solid:
A- Crystalline it has a definite shape may be : Needles, Prisms, Plates,
Microcrystalline
B- Powder may be Fine or Coarse
C-Amorphous (has no definite shape)
Solid-Crystalline- prisms
Solid-Crystalline- needles
Solid-Crystalline- microcrystals
Solid – crystalline-plates
Solid- crystalline- pill
Solid – powder- (coarse or fine)
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Liquid:
A- Mobile (such as : methanol, ethanol)
B- Viscous (such as lactic acid, glycerol)
How you can write the condition?
Condition: solid, crystalline, needles
Condition: solid, crystalline, microcrystal
Condition: solid, powder, fine
Condition: solid, powder, coarse
Condition: liquid, (mobile or viscous)
2-Color:
Note and describe the color of the sample weather its liquid or solid.
Why are some compounds colored?
The colour is due to the presence of Chromophore group (causes extended
NO
conjugation)
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Examples of chromophoric groups : NO2, COOH
Benzene
colourless
Some of expected colors:
Color
Brown
Pink
Colorless turns brown due to air oxidation
Colorless turns to yellow
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Nitrobenzene
Yellow colour
Expected Substance
Higher aromatic amines
Naphthols
Phenols, aniline, aminophenols
Anthracene ,cinnamic acid
3-odour :
if no odor 
odorless
odour
Bitter almond
Expected Substance
Benzaldehyde, nitrobenzene
Mice like odour
Pleasant sweety odour
Vinegar like odour
Fishy odour
Pungent(irritant odour)
Stable like odour
Apple like odour
Phenolic odour
acetamide
Esters-Chloroform
Acetic acid
Aniline
Formaldhyde, lower acids
P-toluidine
Ethyl acetate
Many phenols
4-solubility/miscibility:
First you need to note the following:
Solubility is for solids and we say soluble in.
Miscibility is for liquids and we say miscible with.
Solubility/Miscibility in (with) H2O:
If a solid (liquid) is soluble (miscible) in (with) H2O then you need to
determine whether it's acidic, basic or neutral this can be achieved through the
use of litmus paper.
When a blue litmus paper turns red then the compound is acidic
When a red litmus paper turns blue then the compound is basic
When the two litmus papers don't change in color then the compound is neutral
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Solubility/miscibility in (with) H2O:
miscible
immiscible
heavier
immiscible
lighter
PURIFICATION OF SOLID ORGANIC COMPOUNDS
 Crystallization is : The process in which a solid substance separates
from saturated solution as crystals.
It is a technique which used to purify solid compounds, based on
solubility and depends on:
1) Dissolving organic compounds (solutes) in hot liquids (solvents).
2) Filtration to remove impurities.
3) Cooling the hot solution to precipitate the organic compounds in crystal
form.
Types of solvents:
Polar Solvent: Water, Methanol, Ethanol, Dioxan and Acetic acid.
Non-Polar Solvent: benzene, Chloroform, n-Hexane and Dichloromethane.

Recrystallization used to purify solids based on their different
solubilities.
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Recrystallization Steps:
1- Add a small quantity of appropriate solvent to an impure solid.
2- Apply heat to dissolve the solid.
3- Cool the solution to crystallize the product.
4- Use vacuum filtration to isolate and dry the purified solid.
Ex. : Benzoic acid and Anthracene.
Sublimation is :
" The transition of a substance from the solid phase to the gas phase
without passing through an intermediate liquid phase ".
solid↔ vapor Ex.: Carbon dioxide, Iodine and Naphthalene.
PURIFICATION OF LIQUID ORGANIC COMPOUNDS
Distillation:
- Distillation is the process of heating a liquid until it boils, capturing and
cooling the resultant hot vapors, and collecting the condensed vapors.
-Distillation is used for both identification and purification of organic
compounds .
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Types of Distillation :
1- Simple distillation:
Purification of organic compounds from a non volatile impurities eg,
(solid material).
Simple distillation is designed to evaporate a volatile liquid from a
solution of non-volatile substances; the vapor is then condensed in the
water condenser and collected in the receiver.
Fig. Simple distillation
2-Fractional Distillation:
Mixtures of liquids whose boiling points are similar (separated by less than
70°C) cannot be separated by a single simple distillation.
In these situations, a fractional distillation is used.
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Fig. Fractional Distillation
3-Steam Distillation:
Distillation of 2-immiscible liquids, this technique can be used for
purification of high boiling liquids which decompose near their boiling
points and these liquids are immiscible with water.
Fig. Steam Distillation
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4- Vacuum Distillation
it is used to distill compounds that have a high boiling point or any
compound which might undergo decomposition on heating at atmospheric
pressure.The vacuum is provided either by a water aspirator or by a
mechanical pump.
Fig. Vacuum Distillation
DETERMINATION OF PHYSICAL PROPERTIES FOR ORGANIC
COMPOUNDS
1- Melting Points
The temperature at which the solid phase is in equilibrium with the liquid
phase for the given substanc , or the temperature at which the solid and
liquid have the same vapour pressure. ( solid ↔ liquid ).
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Mixed melting point
Mixed melting points can be used in the following manner to determine
whether two compounds are the same or different even they have similar
melting points. Assuming that a given organic (A) melts sharply at 120 C,
and benzoic acid (compound B) also has melting point at 120 C. Is
compound (A) benzoic acid or different compound?
If compound (A) is benzoic acid, then a mixed melting point of (A) and (B)
will melt sharply at 120 C, i.e. the same as each individual compound alone.
If , on the other hand , compound(A)is not benzoic acid, then the melting
point of a mixture of (A) and (B) will be lowered and the melting range will
be broadened. Since they are different compounds, each behaves as an
impurity in the other.
Fig. Melting point apparatus
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2- Boiling Point
The boiling point is the temperature at which the vapor pressure of the
liquid phase of a compound equals the external pressure acting on the
surface of the liquid.The external pressure is usually the atmospheric
pressure.
EXTRACTION WITH SOLVENTS
 Extraction :
Separation and isolation of organic substances from the mixtures , it can be
subdivided into :
1- Extraction of Solids: e.g. perfume essence from flowers by using solvents
( H2O, CHCL3 )
2-Extraction of solutions : Technique used for isolation dissolved substances
by shaking its solution with immiscible solvent in a separating funnel.
 On standing, the two immiscible phases
(usually organic and
aqueous) from two separate layer (upper and lower) that can be
separated by a means of a separating funnel.
Fig. separating funnel
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CHROMATOGRAPHY
1- Thin Layer Chromatography – TLC is a simple, quick, and
inexpensive
procedure that gives quick answer to
how many
components are in a mixture.
Fig. Thin Layer Chromatography
2- Column Chromatography: A purification technique used to isolates
desired compounds from a mixture.
*The stationary phase, a solid adsorbent, is placed in a vertical glass
(usually) column and the mobile phase, a liquid, is added to the top and
flows down through the column (by either gravity or external pressure).
Fig. Column Chromatography
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3- Gas Chromatography (GC):
In gas chromatography the stationary phase is a high-boiling liquid and
the mobile phase is an inert gas.
*GC is used as an analytical tool to find out how many components are
in a mixture. It can also be used to separate small amounts of material.
Experimental ( 1)
• Objective : Crystallization of Benzoic acid
• Glassware: 2 conical flask , funnel , beaker, glass rod , stand , wire
gauze, clamp .filter paper.
• Chemicals : Benzoic acid , distilled water
• Procedure :
1- Place 2gm of Benzoic acid in a 100ml conical flask
2- Heat 50ml of distilled water to boiling
3- Add the water to the benzoic acid until it dissolve completely using
glass rod
4- Prepare a fluted filter paper and short –stem funnel , place it in a
suitable conical flask and start to filtrate the hot solution rapidly .
5- Leave the filtrate to cool at room temperature
6- Filter the cold solution and collect the pure crystals.
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Experimental ( 2)
Objective : Separating a two-liquid component
Glass ware : separating funnel, 2 conical flask, stand, wire gauze,
clamp holder, filter paper.
Chemicals: Chloroform, water.
Procedure
1- Place 50ml of water and 50ml of chloroform in a separating funnel
2- Shake it well
3- Draw off the lower aqueous layer into a
flask and repeat extraction
of the lower
phase
4- Draw off the other layer into another flask.
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LAB. 2
The qualitative analysis of an organic compound
The qualitative analysis of an organic compound involves the detection of all
the elements present in it. Carbon and hydrogen are generally present in all
organic compounds. Other elements which may be present in organic
compounds are oxygen, nitrogen, sulphur, halogens, phosphorus, etc.
Detection of Carbon and Hydrogen
Carbon and hydrogen are detected by heating the organic compound with
cupric oxide (CuO) strongly, where carbon is oxidized to carbon dioxide and
hydrogen to water. Carbon dioxide is tested by lime water test, whereas
water is tested by anhydrous copper sulphate test.
Fig: Detection of carbon and hydrogen in an organic compound
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Procedure
1- The given organic compound is mixed with dry copper oxide (CuO)
and heated in a hard glass tube.
2- The products of the reaction are passed over (white) anhydrous copper
sulphate and then bubbled through lime water.
3- If copper sulphate turns blue due to the formation of CuSO 4.5H2O (by
water vapor) then the compound contains hydrogen.
4- If lime water is turned milky by CO2, then the compound contains
carbon.
Detection of nitrogen, sulphur and halogens
Nitrogen, sulphur and halogens in any organic compound are detected by
'Lassaigne's test'.
Lassaigne's test
In this reaction we use sodium metal, which fused with the organic
compound (C, N, S or X) to convert these elements into water soluble
sodium salts.
Caution *
While using the sodium metal, following precautions should be taken into
account:
1. Do not touch the sodium metal with your fingers, always use forceps to
handle it.
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2. Unreacted sodium metal should be carefully decomposed by adding small
amount of ethyl alcohol into it.
3. Sodium metal reacts strongly with water, according to the following
reaction
2Na(s) + 2H2O → 2NaOH (aq) + H2(g)
Hydrogen gas (H2) released reacts strongly with oxygen in the air and make
strong explosion.
Apparatus required:
Beaker, conical flask, funnel, test tubes, ignition tubes, capillary tubes, glass
rod, test tube holder, spatula.
Chemicals required:
Organic compound whose extra element is to be determined, sodium metal,
ferrous sulphate, lead acetate sodium nitroprusside, ferric chloride solution,
silver nitrate, aq. NaOH, dil. Sulphuric acid, dil. Nitric acid, dil.
Hydrochloric acid, conc. Nitric acid
Procedure
1- Place 25-30 mg of fresh sodium metal into a dry Pyrex test tube (make
sure that the test tube is undamaged).
2- Add approximately 10 mg of the (anhydrous) compound to be analyzed.
Let the mixture rest for a few minutes.
3- Heat the test tube over a small flame, just enough to melt the sodium.
Then heat more strongly so that the test tube becomes glowing red.
4-When all of the sodium has reacted, add 67 mL of water, heat the mixture
until it boils and filter it.
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5-The filtrate possibly contains sodium cyanide (originates from the
elements of the sample), sulfide and halogens as a alkaline solution. Use the
filtrate in the following tests:
Determination of nitrogen
1-To 1 mL of filtrate , add a few drops of iron(II)sulfate (ferrous sulfate)
solution.
2- Boil the mixture (to oxidize a part of the Fe2+ions to Fe3+ions by oxygen
in air).
3- Acidify the solution by adding 2 M sulfuric acid, a blue green colour or
blue precipitate (prussian blue, Fe4[Fe(CN)6]3) confirms the presence of
cyanide ions.
.
Determination of sulphur
The presence of sulphur in any organic compound is detected by using the
filtrate as follows:
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Lead acetate test
1- A small portion of sodium extract is acidified with acetic acid and lead
acetate solution is added to it.
2- A black precipitate of lead sulphide indicates the presence of sulphur.
Sodium nitroprusside test
1- Add one drop of a fresh, aqueous solution of sodium nitroprusside
Na2[Fe(CN)5NO] to about 1 mL of the filtrate.
2- A pink or purple colour verifies the presence of sulfide ion.
Test for nitrogen and sulphur present together
1-Take 1-2 ml of sodium extract in the test tube and acidify it with dilute
hydrochloric acid.
2- Add 2-3 drops of ferric chloride solution. A blood red colour indicates
the presence of nitrogen and sulphur together.
Na + C
+
N +
S
From organic compound
→
NaCNS
Sodium thiocyanate
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3 NaCNS
+
→
Fe+3
Fe(CNS)3
Ferric thiocyanate (blood red)
Determination of halogens:
Silver Nitrate Test
(a) When nitrogen and / or sulphur are absent
1-Take 1-2 ml of sodium extract in test tube and acidify it with dilute nitric
acid.
2- Add silver nitrate solution (0.5ml).
-A white precipitate soluble in Ammonium hydroxide indicates the
presence of chlorine.
-A pale yellow precipitate soluble in excess of Ammonium hydroxide
solution indicates the presence of bromine.
-A yellow precipitate insoluble in Ammonium hydroxide indicates the
presence of iodine.
(b) When nitrogen and / or sulphur are present
1-Take 1 ml of filtrate in test tube and acidify it with conc. nitric acid (23ml).
2- Boil the mixture to reduce the original volume to half to get rid of HCN
and /or H2S. And now perform the silver nitrate test.
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University of Hail
Faculty of Science
Chemistry Department
2nd Year
Manual Laboratory
Practical Organic Chemistry II
CHEM 271
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