NUTANUNIVERSAL ACADEMY
28/1 2nd floor, Shakti nagar Delhi-7 near Nangia park
PH- 9811177527, 9711543004, 011-23848668, 011-4705646
Subject- Chemistry
Class-XII
1st Pre Board
Time allowed: 3 hour
Maximum marks:70
General Instructions:
(i) All questions are compulsory.
(ii) Marks for each question are indicated against it.
(iii) Question numbers 1 to 8 are very short-answer question and carry 1 marks each.
(iv) Questions number 9 to 18 are short-answer questions and carry 2 marks each.
(v) Question numbers 19 to 27 are also short-answer questions and carry 3 marks each.
(vi) Question numbers 28 to 30 are long-answer questions and carry 5 marks each.
(vii) Use Log Table, if necessary. Use of calculators is not allowed.
1. Write IUPAC name of
CH2Cl
2. Express the relation between conductivity and molar conductivity of a solution held in a cell.
3. Define `electrophoresis’.
4. Draw the structure of XeF2 molecule.
5. Name the defect which increases the density of the substance. Explain it.
6. Draw the structure of 3-methylbutanal.
7. Arrange the following compounds in an increasing order of their solubility in water:
C6H5NH2, (C2H5)2NH, C2H5NH2
8. What are biodegradable polymers?
9. What is leaching. How leaching of alumina is done from bauxite?
10. Determine the values of equilibrium constant (KC) and ∆𝐺 𝑜 for the following reaction:
Ni(s)+2𝐴𝑔+ (𝑎𝑞) → 𝑁𝑖 2+ (𝑎𝑞) + 2𝐴𝑔(𝑠), 𝐸 𝑜 = 1.05 𝑉
(1 𝐹 = 96500 𝐶 𝑚𝑜𝑙 −1)
11. Distinguish between `rate expression’ and `rate constant’ of a reaction.
12. A 23 year old medical student & brave daughter of India was gang raped by six cruel men into a bus
at munrika in south Delhi at 9:30 pm on 16th December 2012. The brave girl was taken to safdarjung
Hospital by the police. Doctors conduct an emergency operation to stabilise the extensively injured
daughter of India. Doctors found “RBC deficiency in her haemoglobin” & found “ Increased blood
clotting time” after her surgery. Suppose Anshu, Mansi, Bharti & Himanshi Bansal of Nutan Universal
Academy Shakti Nagar were discussing about her treatment. Suppose Rohit says to his friends that the
girl must be given two vitamins to minimize RBC deficiency & to reduce blood clotting time. Being a
chemistry student which were the two vitamins said by Rohit what technical name you recommend for
RBC deficiency in haemoglobin. Although the brave girl died on 29th dec 2012 (May God give peace to
her soul). But what value you add to her treatment .
13. What is transition metal? Why Zn, Cd, Hg & Cn (Group 12 elements) are not considered transition
metal.
14. Explain the following giving one example for each:
(i) Reimer- Tiemann reaction.
(ii) Friedel Craft’s acetylation of anisole.
15. How would you obtain
(i) Picric acid (2,4,6-trinitrophenol) from phenol,
(ii) 2-Methylpropene from 2-methylpropanol?
16. What is essentially the difference between 𝛼-form of glucose and 𝛽-form of glucose? Explain
17. Write differences between Globular protein & Fibrous protein.
18. How Biodegradable polymer PHBV prepare. Write its complete equation & uses.
19. Silver crystallizes in face-centered cubic unit cell. Each side of this cell has a length of 400 pm.
Calculate the radius of the silver atom. (Assume the atoms just touch each other on the diagonal across
the face of the unit cell. That is each face atom is touching the four corner atoms.)
20. The 1st order rate constant for the decomposition of ethyliodide by the reaction
C2H5I(𝑔)→C2H4(𝑔)+𝐻𝐼(𝑔) at 600K is 1.6×10-5 S-1 Its energy of activation is 209KJ/ mol calculate the rate
constant of the reaction at 700K. (log(.00636)=-2.197)
21. Explain how the phenomenon of adsorption finds application in each of the following process:
(i) Production of vacuum
(ii) Heterogeneous catalysis
(iii) Froth Floatation process.
OR
Define each of the following terms:
(i) Micelles
(ii) Peptization
(iii) Desorption
22. Describe the principle behind each of the following processes:
(i) Vapour phase refining of a metal.
(ii) Electrolytic refining of a metal.
(iii) Recovery of silver after silver ore was leached with NaCN.
23. Complete the following chemical equation & Balance it.
𝐻𝑒𝑎𝑡𝑒𝑑
(i) K2CrO4 →
𝐻𝑒𝑎𝑡𝑒𝑑
(ii) KMnO4→
(iii) Mn2+ +S2 O82- →
(in acidic medium if one of the product is permanganate ion).
𝐻𝑒𝑎𝑡𝑒𝑑
(iv) H3PO3 →
24. Discuss Hybridisation of [𝐶𝑜𝐹6 ]3- by valence bond Theory.
25. Answer the following:
(i) Haloalkanes easily dissolve in organic solvents, why?
(ii) What is known as a racemic mixture? Give an example.
(iii) Of the two bromoderivatives, C6H5CH(CH3)Br and C6H5CH(C6H5)Br, which one is more reactive in Sn1
substitution reaction and why?
26. (a) Explain why an alkylamine is more basic than ammonia.
(b) How would you convert
(i) Aniline to nitrobenzene?
(ii) Aniline to iodobenzene?
27. Describe the following giving one example for each:
(i) Detergents
(ii) Food preservatives
(iii) Antacids
28. (a) Differentiate between molarity and molality for a solution. How does a change in temperature
influence their values?
(b) Calculate the freezing point of an aqueous solution containing 10.50 g of MgBr2 in 200 g of water.
(Molar mass of MgBr2=184 g)
(Kf for water=1.86 K kg mol-1)
OR
(a) Define the terms osmosis and pressure. Is the osmotic pressure of a solution a colligative property?
Explain.
(b) Calculate the boiling point of a solution prepared by adding 15.00 g of NaCl to 250.0 g of water. (Kb
for water = 0.512 K kg mol-1)
(Molar mass of NaCl = 58.44 g)
29. (a) Give chemical tests to distinguish between
(i) Propanal and Propanone.
(ii) Benzaldehyde and acetophenone.
(b) How would you obtain
(i) But-2-enal from ethanal,
(ii) Butanoic acid from butanol,
(iii) Benzoic acid from ethylbenzene?
OR
(a) Describe the following giving linked chemical equations:
(i) Cannizzaro reaction
(ii) Decarboxylation
(b) Complete the following chemical equation:
(i)
CH2CH3
KMnO4
→
𝐾𝑂𝐻,ℎ𝑒𝑎𝑡
COOH
(ii)
SOCl2
→
ℎ𝑒𝑎𝑡
COOH
(iii) C6H5CONH2
H3O+
→
ℎ𝑒𝑎𝑡
30. (a) Explain.
(i) Why are halogens strong oxidising agents.
(ii) Why Fluorine forms only oxo acid, HOF
(b) Complete the following equation
(i) XeF2 + H2O →
(ii) P4 + NaOH + H2O →
𝐶𝑢𝐶𝑙2
(iii) HCl +O2 →
723K