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
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Mains Paper III, analytical and organic chemistry
Question paper, 2022
UPSC Combined Geo-Scientist, Stage II (Mains). 12 pages, as issued by UPSC.
Every question of 2022, one page each47 parts in 10 questions, with the question as text and the key points of its answer
Question 1 40 marks
- 1(a)Accuracy and precision5 marks
- 1(b)Phases in GLC and choice of carrier gas5 marks
- 1(c)Matching techniques with sources and detectors5 marks
- 1(d)Cold-vapour atomisation for mercury5 marks
- 1(e)Components of a thermogravimetric analyser5 marks
- 1(f)X-rays from radioactive isotopes5 marks
- 1(g)Generation of the argon plasma in ICP–MS5 marks
- 1(h)Manganese in pyrolusite by redox 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)Cyclohexanone: self-condensation with NaOH, none with LDA4 marks
- 6(b)Ethyl acetoacetate with cyclohexanone: Knoevenagel condensation4 marks
- 6(c)Birch reduction of benzoic acid4 marks
- 6(d)HCl with 1-methyl-1-vinylcyclobutane: ring expansion4 marks
- 6(e)Cyclopentadiene with maleic anhydride: endo and exo adducts4 marks
- 6(f)UV absorption of aniline in neutral and in acidic solution4 marks
- 6(g)Aromatic proton shifts: NO₂, COOH and CF₃ as para substituents4 marks
- 6(h)Citral and citronellal by IR: conjugated and isolated C=O4 marks
- 6(i)3-Methyl- and 4-methylpentan-2-one by mass spectrometry4 marks
- 6(j)4-Bromobenzoyl chloride to 4-bromoaniline: Lossen rearrangement4 marks
Question 7 30 marks
Question 8 30 marks
- 8(a)Woodward–Fieser rules: λmax of three unsaturated ketones10 marks
- 8(b)¹H NMR of an enaminone: assignment and the change at 300 MHz5 marks
- 8(c)A diene and an enone in UV light: [2 + 2] cycloaddition5 marks
- 8(d)Photochemical 6π electrocyclic ring closure of an octatriene5 marks
- 8(e)Cope rearrangement of a 1,5-diene with CN and CO₂Et5 marks
Question 9 30 marks
Question 10 30 marks