Indian Forest Service (Mains)
Chemistry optional
- 2 papers
- 200 marks each
- 3 h per paper
Paper II covers organic chemistry and spectroscopy.
Reaction mechanisms: every question, 2021 to 2025
7 parts worth 40 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.
General methods (both kinetic and non-kinetic) of study of mechanism of organic reactions illustrated by examples: use of isotopes, cross-over experiment, intermediate trapping, stereochemistry; energy diagrams of simple organic reactions: transition states and intermediates; energy of activation; thermodynamic control and kinetic control of reactions.
Notes: Methods of studying reaction mechanisms: isotopes, crossover, trapping, kinetic isotope effect (full notes) · short notes
Notes: Stereochemistry and conformational analysis: R/S, E/Z, Fischer and Newman projections, cyclohexane (full notes) · short notes
2025
- Q4(a) Primary kinetic isotope effect10 marks Answered
2024
- Q1(b) Secondary kinetic isotope effect5 marks Answered
- Q2(a)(i) A para-Claisen crossover experiment5 marks Answered
2023
- Q1(b) Evidence for a tetrahedral intermediate5 marks Answered
- Q3(d) Racemization during alpha bromination5 marks Question only
2022
- Q1(c) Tracing the nitrile carbon5 marks Answered
- Q2(e) Deuterium and hydrolysis rate5 marks Question only