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 21 
Pages 3 and 4 of 21
Pages 5 and 6 of 21 Pages 7 and 8 of 21 Pages 9 and 10 of 21 Pages 11 and 12 of 21 Pages 13 and 14 of 21 Pages 15 and 16 of 21 Pages 17 and 18 of 21 Pages 19 and 20 of 21 Page 21 of 21 
Paper II, organic chemistry and spectroscopy
Solution, 2024
UPSC Civil Services (Mains), Chemistry optional. 21 pages. Questions 1, 3, 5, 6 and 8 are answered.
Every question of 2024, 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)(i)Aromatic, non-aromatic or antiaromatic5 marks
- 1(a)(ii)Diphenylcyclopropenone resists nucleophilic addition5 marks
- 1(b)Intermediate in the amination of bromobenzene10 marks
- 1(c)(S)-2-Butanol to (S)-2-butyl chloride10 marks
- 1(d)Name and reagent for five conversions10 marks
- 1(e)Electrocyclic steps of cyclononatriene10 marks
Question 2 50 marks
- 2(a)(i)kH/kD = 7.1 for 2-phenylethyl bromide with ethoxide10 marks
- 2(a)(ii)1,2- and 1,4-addition of HBr to butadiene5 marks
- 2(b)(i)Benzaldehyde with diethyl malonate and pyridine10 marks
- 2(b)(ii)Structure of X; name; proof of syn-elimination5 marks
- 2(c)(i)Products of three reactions15 marks
- 2(c)(ii)2-Methylpent-2-enoic acid by the Reformatsky reaction5 marks
Question 3 50 marks
- 3(a)(i)Methyl cyanide heated with dilute HCl10 marks
- 3(a)(ii)Bromine addition to cis- and trans-2-butene5 marks
- 3(b)(i)Enone from a methoxy triene5 marks
- 3(b)(ii)Classify the rearrangement at 33 °C5 marks
- 3(b)(iii)Methoxy methyl benzoquinone with butadiene5 marks
- 3(c)(i)Acyl chloride to isocyanate; singlet and triplet nitrene10 marks
- 3(c)(ii)Indole at C-3; inertness of chlorobenzene10 marks
Question 4 50 marks
- 4(a)(i)Furan with acetic anhydride and BF₃10 marks
- 4(a)(ii)Major products and mechanism type5 marks
- 4(b)(i)Crossover experiment for the Claisen rearrangement10 marks
- 4(b)(ii)Energy profile: benzene to chlorobenzene5 marks
- 4(c)(i)Major products of three rearrangements10 marks
- 4(c)(ii)Chlorodifluoromethyl phenyl ketone with Ac₂O / AcONa10 marks
Question 5 50 marks
Question 6 50 marks
Question 7 50 marks
Question 8 50 marks
- 8(a)Assignment of four C=O stretching bands15 marks
- 8(b)(i)Ring opening of 2,2-dimethylcyclopropanone by methoxide10 marks
- 8(b)(ii)Order of J(Ha–Hb)5 marks
- 8(c)(i)Two alkenes from 2-chloro-2,3-dimethylbutane10 marks
- 8(c)(ii)Fragmentation of diethyl ether5 marks
- 8(c)(iii)Bond length of HCl from its moment of inertia5 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.
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.