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

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Paper II, organic chemistry and spectroscopy
Solution, 2020
UPSC Civil Services (Mains), Chemistry optional. 21 pages. Questions 1, 2, 5, 6 and 7 are answered on these pages; every question has its full text answer on its own page.
Every question of 2020, one page each28 parts in 8 questions, with the question as text and its full model answer
Question 1 50 marks
- 1(a)Cycloheptatrienyl (tropylium) bromide: an ionic organic bromide10 marks
- 1(b)Carbonium ion and carbocation10 marks
- 1(c)trans-1,2-Dibromo-1-methylcyclohexane from methylcyclohexane10 marks
- 1(d)Why Grignard reactions cannot occur in cells10 marks
- 1(e)Thermal electrocyclisation of (2E,4Z,6E)-octa-2,4,6-triene10 marks
Question 2 50 marks
Question 3 50 marks
Question 4 50 marks
Question 5 50 marks
- 5(a)Tetrafluoroethylene from methane; uses of PTFE10 marks
- 5(b)Chemoselective reduction: NaBH₄ then LiAlH₄10 marks
- 5(c)Photoenolisation and intramolecular Diels–Alder: estrone skeleton10 marks
- 5(d)Aromatic out-of-plane C–H wagging and adjacent hydrogens10 marks
- 5(e)Methyl groups of 7,7-dimethylnorbornene: anisotropy of C=C10 marks
Question 6 50 marks
Question 7 50 marks




















