JEE Main · 2024 · 27 Jan 2024 · Shift 1 · Aldehydes Ketones and Carboxylic Acids

Which of the following has highly acidic hydrogen?

(A)(see structure)
(B)(see structure)
(C)(see structure)
(D)(see structure)
✓ Correct

Answer: (D)

Solution

The most acidic hydrogen is the one flanked by two carbonyl groups (option 4, a

β

-diketone-type active methylene). Removing this proton gives a carbanion whose negative charge is delocalized by resonance onto both adjacent C=O groups, which stabilizes the conjugate base far more than in a compound with only one carbonyl group nearby.

JEE Main · 2024 · 27 Jan 2024 · Shift 1 · Single correct option

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