Question

(a) How carboxylate ion get stabilised by resonance? Explain by the structure.
(b) Carboxylic acids are more acidic than phenols. Explain.

Answer 1

(a) Carboxylate ion get stabilized by resonance. Carboxylate ion is resonance hybrid of two equivalent structures so that the negative charge is delocalised on both oxygen atoms. This leads to stability.
(b) Carboxylic acids are more acidic than phenols. Carboxylate ion has two equivalent resonance structures in which negative charge is delocalised over more electronegative two oxygen atoms. Phenoxide ion has non equivalent resonance structures in which negative charge is delocalized over one oxygen atom and less electronegative carbon atom. Hence, carboxylate ion is more stable than phenoxide ion.