UPSC Combined Geo-Scientist
Chemist
- 3 descriptive papers
- 200 marks each
- 3 h per paper
Mains Paper III covers analytical and organic chemistry.
All years
Mains Paper III, analytical and organic chemistry
Question paper, 2026
UPSC Combined Geo-Scientist, Stage II (Mains). Every question of the 2026 paper is on its own page, with the question as text.
Every question of 2026, one page each43 parts in 10 questions, with the question as text and the key points of its answer
Question 1 40 marks
- 1(a)Classification of samples by size5 marks
- 1(b)Stationary-phase film thickness in gas chromatography5 marks
- 1(c)Percentage of amine from the absorbance of its picrate5 marks
- 1(d)Principle of vapour-generation AAS5 marks
- 1(e)Purge gases in thermogravimetric analysis5 marks
- 1(f)X-ray fluorescence in X-ray diffraction5 marks
- 1(g)Argon in ICP-MS; acids for arsenic5 marks
- 1(h)MnO₂ in pyrolusite by back titration5 marks
Question 2 30 marks
Question 3 30 marks
Question 4 30 marks
Question 5 30 marks
Question 6 40 marks
- 6(a)Hofmann and Schmidt reactions4 marks
- 6(b)Cannizzaro; LiAlH₄ on a lactam; selective reduction of an ester4 marks
- 6(c)Gramine from indole and its displacement by cyanide4 marks
- 6(d)Benzoin condensation and Darzens reaction4 marks
- 6(e)Two epoxidations of carvone4 marks
- 6(f)Photochemistry of stilbene4 marks
- 6(g)Racemisation of an optically active 1,5-diene4 marks
- 6(h)Identify the amide from its IR bands4 marks
- 6(i)Woodward–Fieser rules for three dienes4 marks
- 6(j)Halogens from the M, M+2 and M+4 peaks4 marks