UPSC Combined Geo-Scientist, Mains · 2016 · Mains Paper III
Q7(g). Keto–enol claim: correction
Question
The paper claims A (Meldrum' s acid) exists exclusively as enol and B (2,2-dimethylcyclohexane-1,3-dione) exclusively as keto. Explain the structural effects.
Answer in brief
The first premise is incorrect: Meldrum' s acid is not exclusively enolic. B lacks the central hydrogen needed for its usual conjugated enol.
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CoversKeto–enol claimcorrectionTautomerism
All parts of Question 7
- 7(a) Acidity and hybridisation4 marks
- 7(b) Dichlorocarbene addition4 marks
- 7(c) Grignard addition to a keto ester4 marks
- 7(d) Dipole moment of cyclopropenone4 marks
- 7(e) Cannizzaro reaction4 marks
- 7(f) Frontier orbital nodes4 marks
- 7(g) Keto–enol claim: correction4 marks
- 7(h) Hofmann rearrangement and oxidation4 marks
- 7(i) Carbonyl stretching order4 marks
- 7(j) Carbon count from isotope peaks4 marks