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CHEMISTRY (Theory)/043
Class – XII
Time allowed: 3 hours Maximum Marks: 70
General Instructions:
a) All the questions are compulsory.
b) There are 26 questions in total.
c) Questions 1 to 5 are very short answer type questions and carry one mark each.
d) Questions 6 to 10 carry two marks each.
e) Questions 11 to 22 carry three marks each.
f) Questions 23 is value based question carrying four marks.
g) Questions 24 to 26 carry five marks each.
h) There is no overall choice. However, an internal choice has been provided in one question of
two marks, one question of three marks and all three questions in five marks each. You have
to attempt only one of the choices in such questions.
i) Use of calculators is not permitted. However, you may use log tables if necessary.
1. Give IUPAC name of CH3COCH2COOH.
2. What is the hydrolysis product of (a) Maltose (b) Lactose?
3. The decomposition reaction of ammonia gas on platinum surface has a rate constant k = 2.5 x 10-4 mol /L/S.
What is the order of the reaction?
4. Which is a betterreducing agent C or CO below 673K.
5. Define Glycosidic linkage.
6. What are 12 – 16 and 13 – 15 compounds? Give examples.
7. a) Define Pseudo first order reaction.
b) Give the effect of catalyst on the rate of reaction.
8. Which is a strongeracid phenol or cresol? Explain.
9. a) How is synthetic rubberobtained?
b) Give two examples of biodegradable polymer.
Or
a) Give the difference between Buna-N and Buna-S.
b) Classify the following as addition polymer and condensation polymer Terylene, Bakelite,
PVC, Polythene.
10. Give reasons for the following
a) Frenkel defect does not change the density of AgCl crystal.
b) Pure zinc oxide is white solid but turns yellow on heating.
11. a) Low level of nor-adrenaline is the cause of depression.What type of drugs is needed to cure this problem?
Give two examples.
b) What type of detergent is used for dish washing?
12. Find the Gibbs energy change of the following cell reaction at 298K. Cr|Cr3+(0.1M)||Cu2+(0.01M)|Cu
Given E0cr3+|Cr = -0.75 V and E0 Cu2+|Cu = +0.34 V
13. a) Write down the equations for hydrolysis of XeF4 and XeF6.
b) Which of the above two reactions is a Redox reaction? Give reasons.
14. a) What are the main constituents ofDettol?
b) Why is the use of aspartame limited to cold foods and soft drinks?
c) Give equation for the preparation of non-ionic detergents.Mention the name of their constituents.
Or
i. What are anti-fertility drugs? Give two examples.
ii. Why ranitidine better antacids than sodiumbicarbonate or magnesium hydroxide?
15. a) Which of the following two compounds would react faster by SN2 path way: 1- bromobutane or 2 –
bromobutane. Give reasons.
b) Why allyl chloride is more reactive than n-propyl chloride towards nucleophilic substitution Reaction?
16. An alkene compound ‘A’ (C4H8) which when treated with H2O/H2SO4 gives C4H10O which Cannot be
resolved into optical isomers. Identify ‘A’ with reactions.
17. Distinguish between with appropriate tests of:
a) Propanoyl chloride and propanoic acid.
b) Acetophenone and benzophenone.
c) Phenol and benzoic acid.
18. A metal ion M0+ having d4 valence electronic configuration combines with three didentate ligands
to form a complex compound.Assuming Δ0 > p,
(i) Draw the diagram showing d orbital splitting during this complex formation.
(ii) Write the electronic configuration of the valence electrons of the metal Mn+ ion in terms of t2g and eg.
(iii) What type of hybridization will Mn+ ion have?

(iv) Name the type of isomerism exhibited by this complex.
19. Calculate the amount of KCl which must be added to 1 kg of water so that the freezing point is
depressed by 2k.
20. Explain each of the following
a. Nitrogen is much less reactive than phosphorus
b. The stability of +5 oxidation state decrease down the group 15.
c. Bleaching action of SO2 is temporary.
21. The Rate of a particular reaction triples when temperature change from 500 C to 1000 C. calculate
the activation energy of the reaction.[Given log 3=0.4771; R = 8.314 JK-1 mol-1]
22. Amino acids may be acidic, alkaline or neutral. How does this happen? What are essentialand non-essential
amino acids? Name one of each type.
23. Mrs. Kalra along with their five neighbourlive near a lake. They were living there since last five Years.
When they shifted there, the lake was very beautiful but now it contains a number of Phytoplanktons.One day
Ravi, son of Kalra after coming from schooladvised his Motherand her neighbour not to wash the clothes with
detergent but use natural soaps for this purpose of you want to control the growth of phytoplankton.Mrs. Kalra
and her neighbourfollow this advice and got the beauty of the lake.
Read the above passage and answerthe following question
a. What values are expressed by Ravi and His mother?
b. Why phytoplanktons growexcessively while they were using detergents?
24. A translucent white waxy solid (A) on heating in an inert atmosphere is converted to its allotropic form (B).
Allotrope (A) on reaction with very dilute aqueous KOH liberates a highly poisonous gas (C) having rotten fish
smell. With excess of chlorine forms (D) which hydrolyses to compound (E). Identify compounds (A) to (E) .
Or
Explain the following properties of transition elements:
a) Enthalpy of atomization.
b) Variable oxidation state.
c) Coloured complex formation.
25. a) Derive the relationship between relative lowering of vapourpressure and mole fraction of the volatile
liquid.
b) i) Benzoic acid completely dimerises in benzene. What will be the vapourpressure of a solution containing
61g of benzoic acid per 500g benzene when the vapour pressure of pure benzene at the temperature of
experiment is 660 torr?
ii) What would have been the vapourpressure in the absence of dimerization?
Or
a) Which aqueous solution has higherconcentration 1 molar or l molal solution of the same solute? Give reason.
b) 0.5g KCl was dissolved in 100g water and the solution originally at 200C, freeze at - 0.240C. Calculate the
percentage ionization of salt. Kf per 1000g of water = 1.86K.
26. The compounds A and B dehydrobrominates to give the same alkene C which can regenerate both these
compounds by the addition of HBr in presence and absence of hydrogen peroxide respectively. On hydrolysis,A
and B gives isomeric products D and E respectively. Reaction of C with benzene in presence of hydrogen ions
yields 1,1-diphenylethane. Give the structure of the compounds A to E with reactions.
Or
An organic compound ‘A’ (C8H6) reacts with dilute H2SO4 and HgSO4 giving ‘B’ which reacts with NaOH and
I2 forming compounds ‘C’ and ‘D’. ‘D’ upon reaction with soda lime gives hydrocarbon ‘E’ which on reaction
with acetyl chloride in presence of anhydrous aluminium chloride gives ‘B’. Identify A,B,C,D and E and write
the reaction equation.

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