UPSC Combined Geo-Scientist, Mains · 2020 · Mains Paper III
Q6(j). Distinguishing three carbonyl compounds by proton NMR
Question
Distinguish ethyl acetate (I), methyl propionate (II) and butan-2-one (III) by ¹H NMR.
Answer in brief
The oxygen-bound alkyl signal differentiates the two esters; the ketone has no O-alkyl resonance.
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CoversDistinguishing three carbonyl compounds by proton NMRNMR identification
All parts of Question 6
- 6(a) Dichlorocarbene ring expansion4 marks
- 6(b) Anionic polymerisation of substituted styrenes4 marks
- 6(c) Cyanohydrin formation and hydrolysis4 marks
- 6(d) Doebner condensation4 marks
- 6(e) Hydration with skeletal rearrangement4 marks
- 6(f) Diene reactivity in Diels–Alder reactions4 marks
- 6(g) Norrish II reactivity4 marks
- 6(h) UV maximum of a dienone4 marks
- 6(i) Carbonyl stretching frequencies4 marks
- 6(j) Distinguishing three carbonyl compounds by proton NMR4 marks