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, 2017
UPSC Civil Services (Mains), Chemistry optional. 23 pages. Questions 1, 2, 3, 5 and 6 are answered on these pages; every question has its full text answer on its own page.
Every question of 2017, one page each38 parts in 8 questions, with the question as text and its full model answer
Question 1 50 marks
- 1(a)Aromatic, anti-aromatic or non-aromatic10 marks
- 1(b)E2 of 2-bromo-2-methylpentane: Zaitsev and Hofmann10 marks
- 1(c)Diethylamine and 2-fluoro-1-acetylcyclohexene: addition–elimination10 marks
- 1(d)LDA at -78°C: kinetic enolate of 2-phenylcyclohexanone10 marks
- 1(e)Electrocyclic closure of (2E,4E)-hexa-2,4-diene: FMO10 marks
Question 2 50 marks
Question 3 50 marks
- 3(a)Acetylacetone with MeMgI; conversion to hexane-2,4-dione10 marks
- 3(b)Tertiary alcohol with two identical alkyl groups; Lucas test10 marks
- 3(c)Tosylation, S_N₂ by acetate and hydrolysis: a Walden cycle10 marks
- 3(d)Intramolecular Cannizzaro of furylglyoxal; furoin10 marks
- 3(e)Morpholine and 4-fluorophenyl methyl sulfone: S_NAr10 marks
Question 4 50 marks
- 4(a)Epoxidation, then intramolecular opening by a nitrile anion10 marks
- 4(b)3-Bromoanisole and amide ion: benzyne regiochemistry10 marks
- 4(c)SeO₂ allylic oxidation; dihydroxylation and selective oxidation10 marks
- 4(d)E2 of menthyl and neomenthyl chlorides: anti-periplanar requirement10 marks
- 4(e)But-2-yne to cis- and trans-but-2-ene10 marks
Question 5 50 marks
- 5(a)Thermally forbidden [1,3]-H shift; rules for sigmatropic reactions10 marks
- 5(b)Cyclohexanone to cyclohexanecarbaldehyde in two steps10 marks
- 5(c)Simmons–Smith reaction directed by an allylic OH10 marks
- 5(d)Regiospecific reaction; aniline to p-phenylenediamine10 marks
- 5(e)IR distinction of two pairs of compounds10 marks
Question 6 50 marks
- 6(a)Norbornadiene with TCNE; ring opening of a cis-cyclobutene10 marks
- 6(b)Thermal cyclisation of pentadienyl anion and cation10 marks
- 6(c)Photochemistry of butadiene (S1, T1) and of pentan-2-one (Norrish I, II)10 marks
- 6(d)Photodecarbonylation of norcamphor and bicyclo[3.2.0]heptan-3-one10 marks
- 6(e)Nucleosides, nucleotides; primary structure of DNA and RNA10 marks
Question 7 50 marks
Question 8 50 marks






















