CBSE Class 12 Chemistry Question Paper 2021 Set 03 Solved

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Official CBSE Exam Papers for Class 12 Chemistry

Explore authentic exam materials through the CBSE Class 12 Chemistry Question Paper 2021 Set 03 Solved. Tailored for Class 12 learners, utilizing these Chemistry previous year papers ensures thorough preparation and strengthens time management skills before final CBSE evaluations.

Solved Previous Year Papers for Chemistry

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Section -A
 
1. How much charge in Faradays is required for the reduction of 1 mol of Cu2+ to Cu.
OR
Name the products of electrolysis of aqueous NaCl at different electrodes.
 
2. Define the term receptors. 
 
3. What is Hinsberg reagent. Give its use 
 
4. The dissolution of ammonium chloride in water is an exothermic process, but still it dissolves in water readily. Why?
OR
Addition of mercuric iodide to an aqueous solution of KI shows increase in vapour pressure. Why?
 
5. Which compound in each of the following pair will react faster in SN1 reaction?
CH3CH=CHCl or CH2=CHCH2Cl
 
Section -B
 
6. a) Write the IUPAC name of the following
C6H5CH(OH)CH2CH=CHCH3
b) Draw the structure of 3-Isobutyl-2-oxocyclohexanecarbaldehyde.
 
7. Explain the following
a) Peptide linkage
b) Pyranose structure of α- D (+)glucose
 
8. a) For a reaction A + H2O→B; r = k [A]. What is its (i) Molecularity (ii) Order?
b) The conversion of molecule X to Y follows second order kinetics. If concentration of X is doubled how will it affect the rate of the reaction?
 
9. Explain the thermodynamic principles of metallurgy. 
 
10. Write short note on
a) Zaitsev rule
b) Racemisation
OR
Explain the following with example
a) Wurtz Fittig reaction
b) Freons
 
11. a) Give a chemical test to distinguish aniline and N-methyl aniline.
b) Arrange the following in decreasing order of pKb values :
C2H5NH2, C6H5NHCH3, (C2H5)2NH and C6H5NH2
OR
Write the structures of main products when benzene diazonium chloride reacts with the following reagents
a) H3PO2 +H2O
b) CuCN/KCN
 
12. What is the difference between elastomers and fibres. Give one example of each type. 
 
Section - C
 
13. The freezing point of a solution containing 0.3 g of acetic acid in 30 g benzene is lowered by 0.450C. Calculate Van’t Hoff factor. (Kf for benzene = 5.12 K kg mol-1)
OR
The vapour pressures of pure liquids a and B are 450 and 750 mm of Hg at 350 k respectively. Find out the composition of the liquid mixture if total vapour pressure is 600mm of Hg.Also find the composition of the vapours of these liquids in vapour phase.
 
14. a) Why water cannot be separated completely from ethyl alcohol by fractional distillation?
b) What type of deviation is shown by a mixture of ethanol and acetone? Give reason
c) Gas (A) is more soluble than gas (B) at the same temperature. Which of the two gases will have higher value of KH and why?
 
15. Suggest a mechanism for the dehydration of ethanol using conc.H2SO4 at 413K.
OR
Give reason for the following observations;
a) Phenol is less acidic than 2-Fluoro phenol
b) Tert-butanol is more volatile than n-butanol
c) Di-tert-butyl ether cannot be prepared by Wiliamsons synthesis
 
16. What happens when
a) Chlorobenzene is subjected to hydrolysis
b) Propene is treated with Cl2 in the presence of U.V. light / heated.
c) Alkyl chlorides when treated with NaI in dry acetone
 
17. Outline the principles of refining of metals by the following methods :
a) Zone refining
b) Electrolytic refining
c) Vapour phase refining
 
18. The density of lead is 11.35 g/cm3and the metal crystallises with fcc unit cell. Estimate the radius of lead atom.
( GAM of lead =207g/mol)
 
19. Account for the following
a) Frenkel defects are not found in alkali metal halides.
b) The electrical conductivity of a metal decreases with rise in temperature.
c) Impurity doped silicon is a semiconductor
 
20. Write equations for the following name reactions:
a) Gattermann - Koch reaction.
b) Stephen reaction.
c) Hell Volhard Zelinsky reaction
 
21. a) What are the expected products of hydrolysis of lactose?
b) Explain essential amino acids with one example
c) Give one structural difference between amylose and amylopectin.
 
22. Write the name and structures of the monomers of
a) Nylon-2,6
b) PAN
c) Neoprene
OR
a) Explain why Sulphur is added during vulcanization of rubber?
b) Give any two uses of PHBV
c) Classify the following as condensation and addition polymers Terylene, Bakelite, PVC, Polythene
 
23. a) List two major classes of antibiotics
b) Give two examples of artificial sweetners
c) Why are Cimetidine and ranitidine better antacids than sodium hydrogen carbonate or magnesium hydroxide?
OR
Define the following
a) Tranquilizers
b) Competitive inhibitors
c) Antihistamines
 
24. Account for the following :
a) Aromatic amines are less basic than aliphatic amines
b) Acetylation of aniline reduces its activation effect
c) Nitration of aniline gives substantial amount of m-nitro aniline


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CBSE Class 12 Chemistry Question Paper 2021 Set 03 Solved & Previous Year Question Papers for Class 12 Chemistry

Download CBSE Class 12 Chemistry Question Paper 2021 Set 03 Solved for Class 12 Chemistry

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Are the solutions for CBSE Class 12 Chemistry Question Paper 2021 Set 03 Solved based on the official CBSE marking scheme?

Yes, the solutions for CBSE Class 12 Chemistry Question Paper 2021 Set 03 Solved are prepared by subject matter experts as per official marking scheme. Class 12 students will understand the structure of answers and 'step-marks' methodology Chemistry.

How does solving CBSE Class 12 Chemistry Question Paper 2021 Set 03 Solved help in preparing for the 2026 exams?

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Yes, where applicable, CBSE Class 12 Chemistry Question Paper 2021 Set 03 Solved is available in both English and Hindi mediums. All students from Class 12 can access Chemistry study material in their preferred language.

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