UPSC Combined Geo-Scientist
Chemist
- 3 descriptive papers
- 200 marks each
- 3 h per paper
Mains Paper III covers analytical and organic chemistry.
All topics
Mains Paper III, analytical and organic chemistry
Oxidation and reduction: every question, 2016 to 2025
21 parts worth 118 marks have been set on this unit in UPSC Geo-Scientist Chemistry Mains Paper III from 2016 to 2025. Each one opens on its own page with the question, the answer in brief and the key points.
Syllabus
Reduction of C=C, Meerwein-Ponndorf reaction, Wolff-Kishner and Birch reduction. Oxidation of C=C, hydration, hydroxylation, hydroboration, ozonolysis, epoxidation, Sharpless epoxidation.
Notes: Reagents for oxidation, reduction and hydroboration (full notes) · short notes
2025
- Q8(a)(i) 6,6-Dimethylfulvene takes up hydride; a simple alkene does not5 marks Question only
- Q8(a)(ii) Doped and non-doped conducting polymers; polyacetylene5 marks Question only
- Q9(b)(ii) Sharpless asymmetric epoxidation of an allylic alcohol5 marks Answered
2024
- Q6(f) trans- and cis-Cyclohexane-1,2-diol from cyclohexanone4 marks Answered
- Q7(d)(ii) Epoxidation, then acid-catalysed ring expansion to a ketone5 marks Answered
- Q9(d)(i) Birch reduction with ring closure: a spiro acid5 marks Answered
- Q10(a)(ii) Benzophenone with aluminium isopropoxide at 250 °C5 marks Question only
2023
- Q6(b) Ozonolysis of camphene, then Wolff–Kishner reduction4 marks Answered
- Q8(a) Birch reduction of anisole, then hydrolysis of the enol ether10 marks Question only
2022
- Q6(c) Birch reduction of benzoic acid4 marks Answered
2020
- Q9(d) Stereoselective NaBH₄ reduction10 marks Question only
- Q10(c) Chemoselective epoxidation10 marks Answered
2019
- Q6(a) Ozonolysis of an exocyclic alkene4 marks Answered
- Q9(b) Birch reduction–alkylation sequence of a methoxybenzoic acid10 marks Question only
2018
- Q6(a) Epoxidation and anti opening4 marks Answered
- Q6(i) Rearranged alkylation and Birch reduction4 marks Answered
- Q6(j) Hydroboration–oxidation4 marks Answered
- Q7(a) Epoxidation reactivity5 marks Answered
- Q7(c)(i) Dakin oxidation5 marks Answered
- Q8(c) Reagents for an alkyne-to-alkene transformation5 marks Question only
2016
- Q9(a) Meerwein–Ponndorf–Verley reduction5 marks Answered
Printed copy and Kindle
UPSC Combined Geo-Scientist (Main) Chemistry Paper III: Model Answers 2021 to 2025
- All ten questions of each paper, with the question printed above its answer
- Instruments drawn as labelled diagrams, numericals worked with units
- Topic-wise weightage and a topic-wise index