Indian Forest Service (Mains)
Chemistry optional
- 2 papers
- 200 marks each
- 3 h per paper
Paper II covers organic chemistry and spectroscopy.
All topics
Paper II, organic chemistry and spectroscopy
Substitution reactions: every question, 2021 to 2025
21 parts worth 130 marks have been set on this unit in UPSC IFoS 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
SN1, SN2, SNi, SN1′, SN2′, SNi′ and SRN1 mechanisms; neighbouring group participation; electrophilic and nucleophilic reactions of aromatic compounds including simple heterocyclic compounds: pyrrole, thiophene, indole.
Notes: Aromatic substitution: electrophilic, nucleophilic and heterocycles (full notes) · short notes
Notes: Aliphatic nucleophilic substitution: SN1, SN2, SNi and neighbouring group participation (full notes) · short notes
2025
- Q1(c) Electrophilic substitution of heteroarenes5 marks Answered
- Q2(a) Neighbouring acetate participation10 marks Question only
- Q4(b) Nucleophilic aromatic substitution10 marks Answered
- Q4(d) Pyrrole with chloroform and base10 marks Answered
- Q8(c) Metalation of thiophene5 marks Answered
2024
- Q3(a) Vilsmeier acylation of pyrrole10 marks Question only
2023
- Q1(d) Para-alkyl effects on benzyl solvolysis5 marks Answered
- Q2(b) Halohydrin cyclization and chair populations10 marks Answered
- Q3(b)(i) Nitration of p-bromoanisole3 marks Question only
- Q3(b)(ii) Nitration of p-chloroanisole2 marks Question only
2022
- Q1(e) Substituent effects on aryl negative charge5 marks Answered
- Q1(f) Why DMSO accelerates many SN2 reactions5 marks Answered
- Q3(a)(i) Amination of 2-chloropyridine5 marks Answered
2021
- Q2(b) Hydrolysis of tert-butyl chloride10 marks Answered
- Q2(c)(i) p-Toluidine to m-bromotoluene5 marks Answered
- Q3(d)(ii) Cyanide substitution on a nitroaryl halide5 marks Answered
- Q4(c)(i) Substitution versus elimination of a primary bromide5 marks Question only
- Q4(c)(ii) Alcohol to chloride with retention5 marks Question only
- Q5(f) Nitration of indole5 marks Answered
- Q7(a)(i) A beta-chloroamine and sulfonyl chloride5 marks Question only
- Q7(c)(i) Solvolysis of a tertiary allylic bromide5 marks Question only