UPSEE 2018 Solved Paper

CH3−

O

∥ C

-COOH is strongest acid among all even stronger than CH3−

O

∥ C

-COOH due to electrophilic carbonyl group in it.
Among all carboxylic acids given, CH3−

O

∥ C

-COOH is strongest acid because it has least +I effect of alkyl group present.
Alkyl group present in carboxylic acid has electron donating inductive effect, that increases electron density in the O−H bond. As a result, release of H+ ions form the carboxylic acid will be more difficult.