(N/A) The resonance structures of the phenoxide ion are shown in the figure.
It can be observed from the resonance structures of the phenoxide ion that in structures $II$,$III$,and $IV$,less electronegative carbon atoms carry a negative charge. Therefore,these three structures contribute negligibly to the resonance stability of the phenoxide ion.
Hence,these structures can be ignored. Only structures $I$ and $V$ carry a negative charge on the more electronegative oxygen atom.
The resonance structures of the carboxylate ion are also shown in the figure.
In the case of the carboxylate ion,resonating structures $I'$ and $II'$ contain a negative charge carried by a more electronegative oxygen atom.
Further,in resonating structures $I'$ and $II'$,the negative charge is delocalized over two oxygen atoms. However,in resonating structures $I$ and $V$ of the phenoxide ion,the negative charge is localized on the same oxygen atom. Therefore,the resonating structures of the carboxylate ion contribute more towards its stability than those of the phenoxide ion. As a result,the carboxylate ion is more resonance-stabilized than the phenoxide ion. Hence,carboxylic acid is a stronger acid than phenol.