Question

Account for the following:

Carboxylic acid is a stronger acid than phenol.

Answer 1

Carboxylic acids are acidic due to resonance stabilisation of carboxylate anion and in phenols, acidic character is present due to resonance stabilisation of phenoxide anion. Carboxylic acids are more acidic than phenols because the negative charge in carboxylate anion is more spread out compared to the phenoxide ion, as there are two electronegative O-atoms in carboxylate anion compared to one in phenoxide ion. In the resonance structures of carboxylate anion, the negative charge is present on the O-atoms, while in resonance of phenoxide ion, negative charge is also present on electropositive carbon atom, which leads to less stability of phenoxide ion than carboxylate anion.