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, 2023
UPSC Combined Geo-Scientist, Stage II (Mains). 11 pages, as issued by UPSC.
Every question of 2023, one page each48 parts in 10 questions, with the question as text and the key points of its answer
Question 1 40 marks
- 1(a)Relative standard deviation of replicate results5 marks
- 1(b)HPLC against GLC; particle size of packed GLC columns5 marks
- 1(c)Sources of radiation for infrared spectrometry5 marks
- 1(d)Graphite-furnace AAS compared with flame AAS5 marks
- 1(e)Calibration of the temperature axis in thermogravimetry5 marks
- 1(f)K and L lines in XRF; wavelength-dispersive spectrum of Zn5 marks
- 1(g)Interference of calcium in the ICP–MS determination of iron5 marks
- 1(h)Type metal: constituents and non-destructive analysis5 marks
Question 2 30 marks
Question 3 30 marks
Question 4 30 marks
Question 5 30 marks
Question 6 40 marks
- 6(a)Chlorocarbene from CH₂Cl₂; ring expansion of 3-methylindole4 marks
- 6(b)Ozonolysis of camphene, then Wolff–Kishner reduction4 marks
- 6(c)Reductive amination, then intramolecular aza-Michael addition4 marks
- 6(d)Benzaldehyde and ethane-1,2-dithiol: a 1,3-dithiolane4 marks
- 6(e)Amidomercuration–demercuration of hex-1-ene in acetonitrile4 marks
- 6(f)Dimerisation of cyclopentadiene: endo rule by frontier orbitals4 marks
- 6(g)Two isomeric esters C₇H₁₄O₂ from ¹H NMR4 marks
- 6(h)Mass spectrum of 3-butyn-2-ol: the ion of m/z 554 marks
- 6(i)Acetone: solvent shift of the n → π* band4 marks
- 6(j)Butyrophenone: McLafferty rearrangement and α-cleavage4 marks
Question 7 30 marks
Question 8 30 marks
Question 9 30 marks