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, 2018
UPSC Combined Geo-Scientist, Stage II (Mains). 10 pages, as issued by UPSC.
Every question of 2018, one page each59 parts in 10 questions, with the question as text and the key points of its answer
Question 1 40 marks
- 1(a)Carbonate titration endpoint5 marks
- 1(b)Medium for iodimetry5 marks
- 1(c)Magnesium and the EBT endpoint5 marks
- 1(d)Source modulation in AAS5 marks
- 1(e)Chromatographic zone broadening5 marks
- 1(f)ICP multielement capability5 marks
- 1(g)Alkaline glass-electrode error5 marks
- 1(h)Electron-capture selectivity5 marks
Question 2 30 marks
Question 3 30 marks
Question 4 30 marks
Question 5 30 marks
Question 6 40 marks
- 6(a)Epoxidation and anti opening4 marks
- 6(b)Conjugate addition and dehydrogenation4 marks
- 6(c)Houben–Hoesch acylation4 marks
- 6(d)Pyrrole: formylation and expansion4 marks
- 6(e)Double Michael addition and Dieckmann closure4 marks
- 6(f)Sequential electrocyclic reactions4 marks
- 6(g)Benzyne trapped by isoindole4 marks
- 6(h)Pinacol rearrangement pathways4 marks
- 6(i)Rearranged alkylation and Birch reduction4 marks
- 6(j)Hydroboration–oxidation4 marks
Question 7 30 marks
Question 8 30 marks
Question 9 30 marks
- 9(a)Chlorotriphenylmethane with silver: the trityl radical5 marks
- 9(b)Product and stereochemistry of an acid-catalysed silyl reaction5 marks
- 9(c)Electrocyclic product by Woodward–Hoffmann rules5 marks
- 9(d)Synthetic sequence for a given transformation5 marks
- 9(e)Aromaticity and methyl shifts of a dimethyldihydropyrene system10 marks
Question 10 30 marks
- 10(a)Phenolic OH band shapes5 marks
- 10(b)Cyclic ether identification5 marks
- 10(c)(i)Most downfield proton2 marks
- 10(c)(ii)Highest carbonyl frequency2 marks
- 10(c)(iii)Odd nominal molecular mass2 marks
- 10(c)(iv)Most upfield carbon2 marks
- 10(c)(v)Longest-wavelength diene band2 marks
- 10(d)Phenethyl alcohol spectra10 marks