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
Reactive intermediates: every question, 2021 to 2025
12 parts worth 100 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
Generation, geometry, stability and reactions of carbonium ions and carbanions, free radicals, carbenes, benzynes and nitrenes.
Notes: Reactive intermediates: carbocations, carbanions, radicals, carbenes, nitrenes, benzyne (full notes) · short notes
2025
- Q1(d) Spin state of a carbene; p-bromophenol with NaNH₂10 marks Answered
- Q2(b)(ii) Styrene with BrCCl₃ under light5 marks Question only
- Q3(c)(ii) Photolysis of the α-diazoketone in methanol10 marks Answered
2024
- Q1(b) Intermediate in the amination of bromobenzene10 marks Answered
- Q3(c)(i) Acyl chloride to isocyanate; singlet and triplet nitrene10 marks Answered
2023
- Q1(b)(ii) Dimerisation ability of three triarylmethyl-type radicals5 marks Answered
- Q2(b)(iii) Ketene, hν, then cis-but-2-ene10 marks Answered
2022
- Q2(b)(ii) 1,2-Dihydronaphthalene with NBS, then sodium ethoxide5 marks Question only
- Q4(a)(ii) Loss of optical activity of an imine with sodium ethoxide5 marks Answered
- Q4(b)(i) Dibromocyclopentanes from cyclopentane and excess bromine10 marks Answered
2021
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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