UPSC Civil Services (Mains)
Chemistry optional
- 2 papers
- 250 marks each
- 3 h per paper
- 5 of 8 questions, Q1 and Q5 compulsory
Paper II covers organic chemistry and spectroscopy.
All years
Pages 1 and 2 of 26 
Pages 3 and 4 of 26 
Pages 5 and 6 of 26
Pages 7 and 8 of 26 Pages 9 and 10 of 26 Pages 11 and 12 of 26 Pages 13 and 14 of 26 Pages 15 and 16 of 26 Pages 17 and 18 of 26 Pages 19 and 20 of 26 Pages 21 and 22 of 26 Pages 23 and 24 of 26 Pages 25 and 26 of 26 
Paper II, organic chemistry and spectroscopy
Solution, 2022
UPSC Civil Services (Mains), Chemistry optional. 26 pages. Questions 1, 4, 5, 6 and 8 are answered.
Every question of 2022, one page each44 parts in 8 questions, with the question as text and the key points of its answer
Question 1 50 marks
- 1(a)Ionisation of 3,4-dichloro-1,2,3,4-tetramethylcyclobutene in SbF₅–SO₂10 marks
- 1(b)(4-Nitrophenyl)oxirane with methoxide in methanol10 marks
- 1(c)The reaction that is not a condensation, and its mechanism10 marks
- 1(d)Acid-catalysed rearrangement of two phenyl-substituted 1,2-diols10 marks
- 1(e)Heating cyclopentadiene10 marks
Question 2 50 marks
- 2(a)Products X and Y in three reactions15 marks
- 2(b)(i)2,2-Dimethyltetrahydrofuran with one equivalent of HI5 marks
- 2(b)(ii)1,2-Dihydronaphthalene with NBS, then sodium ethoxide5 marks
- 2(b)(iii)Alkenes from 2-chloro-2,3-dimethylpentane with sodium ethoxide5 marks
- 2(c)(i)Matching three heterocycle syntheses; mechanism of the indole synthesis10 marks
- 2(c)(ii)L-Dopa from L-tyrosine10 marks
Question 3 50 marks
- 3(a)Acetal and ortho-ester Claisen rearrangements of an allylic alcohol15 marks
- 3(b)(i)Ergosterol, precalciferol and the need for sunlight10 marks
- 3(b)(ii)p-Bromonitrobenzene to m-bromobenzoic acid5 marks
- 3(c)(i)Cl₂CH–CF₃ with ethoxide: product and energy profile10 marks
- 3(c)(ii)SN2 reactivity of four tertiary bromides10 marks
Question 4 50 marks
Question 5 50 marks
- 5(a)Nucleosides, nucleotides and the primary structure of DNA and RNA10 marks
- 5(b)Photolysis of 2-methylcyclohexanone in solution10 marks
- 5(c)(i)1-Ethynylcyclopentanol from acetylene5 marks
- 5(c)(ii)Products W, X, Y and Z from toluene5 marks
- 5(d)N–H stretching of amines in IR; alcohols in PMR10 marks
- 5(e)Matching three sets of IR and NMR data with five structures10 marks
Question 6 50 marks
- 6(a)(i)Photolysis of a mixture of valerophenone and 5,5-dideuteriohexan-2-one5 marks
- 6(a)(ii)Photolysis of 4,5-dimethylheptan-2-one10 marks
- 6(b)(i)Polypropylene by Ziegler–Natta catalysis10 marks
- 6(b)(ii)Perlon (nylon-6) from ε-caprolactam5 marks
- 6(c)(i)OsO₄, then HIO₄, on an alkenyl cyclopropane lactone10 marks
- 6(c)(ii)(S)-3-Phenylbutan-2-one with m-CPBA10 marks
Question 7 50 marks
- 7(a)Secondary structures of proteins compared with tertiary structure15 marks
- 7(b)(i)Butanoyl chloride with 2 NaBH₄, then H₃O⁺10 marks
- 7(b)(ii)But-2-yne with sodium in liquid ammonia5 marks
- 7(c)(i)Compound A (M = 102) and its cleavage products B and C10 marks
- 7(c)(ii)Three isomeric carbonyl compounds C₅H₁₀O10 marks
Question 8 50 marks
- 8(a)(i)Carbonyl stretching frequency of two acetylcyclohexenes5 marks
- 8(a)(ii)Dehydration of 1,2-dimethylcyclohexanol; telling the alkenes apart by IR10 marks
- 8(b)(i)λmax of two polyenes by Woodward–Fieser rules10 marks
- 8(b)(ii)λmax of 1,3-butadiene and 1,3,5-hexatriene5 marks
- 8(c)(i)McLafferty rearrangement; fragmentation of butyl butyrate10 marks
- 8(c)(ii)C₂H₂BrCl with J = 16 Hz; two dienones from UV data10 marks
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Model answer pages open with the VKC plan.
Model answer pages open with the VKC plan.
Model answer pages open with the VKC plan.
Model answer pages open with the VKC plan.
Model answer pages open with the VKC plan.
Model answer pages open with the VKC plan.
Model answer pages open with the VKC plan.
Model answer pages open with the VKC plan.
Printed copy and Kindle
UPSC Civil Services (Main) Chemistry Paper II: Model Answers 2021 to 2025
The book has all five years of Paper II in one volume, with every question printed above its answer, mechanisms labelled on the scheme, the topic-wise weightage of marks and a topic-wise index.