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
Question paper, 2024
UPSC Civil Services (Mains), Chemistry optional. 19 pages, as issued by UPSC.
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