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 topics
Paper II, organic chemistry and spectroscopy
Addition reactions: every question, 2021 to 2025
15 parts worth 115 marks have been set on this unit in UPSC CSE Chemistry Paper II from 2021 to 2025. Each one opens on its own page with the question, the answer in brief and the key points.
Syllabus
Electrophilic addition to C=C and C≡C; nucleophilic addition to C=O, C≡N, conjugated olefins and carbonyls.
Notes: Addition to C=C and C≡C: Markovnikov, stereochemistry, dienes (full notes) · short notes
2025
- Q2(b)(i) Acid-catalysed hydration of 3,3-dimethylbut-1-ene10 marks Question only
- Q3(a)(ii) Ketone A from isobutanol alone5 marks Answered
- Q3(b)(i) Cyclopropane from tert-butyl chloroacetate and ethyl acrylate10 marks Answered
- Q3(b)(ii) Structures of C and D5 marks Answered
- Q3(c)(i) Missing reagents and intermediate10 marks Answered
2024
- Q2(a)(ii) 1,2- and 1,4-addition of HBr to butadiene5 marks Question only
- Q3(a)(i) Methyl cyanide heated with dilute HCl10 marks Answered
- Q3(a)(ii) Bromine addition to cis- and trans-2-butene5 marks Answered
2023
- Q4(a)(i) Norbornene with D–Br5 marks Question only
- Q4(a)(ii) Relative rates of bromination in methanol5 marks Question only
- Q4(a)(iii) Hydroboration–oxidation of a tetrasubstituted alkene10 marks Question only
2022
- Q4(a)(i) trans-But-2-ene with perbenzoic acid, then hydroxide10 marks Answered
2021
- Q1(d) Two aldehydes towards a nucleophile in the presence of BF₃·OEt₂10 marks Answered
- Q4(b)(i) 3,3-Dimethylbut-1-ene with HCl5 marks Question only
- Q4(b)(ii) Allyl bromide with HBr, without and with benzoyl peroxide10 marks Question only
Printed copy and Kindle
UPSC Civil Services (Main) Chemistry Paper II: Model Answers 2021 to 2025
- All eight questions of each paper, with the question printed above its answer
- Mechanisms drawn out and labelled on the scheme
- Topic-wise weightage and a topic-wise index