Question
Tue February 19, 2013 By:

Although phenoxide ion has more no. of resonating structure than carboxylate ion,carboxylic acid is a stronger acid than phenol.GIVE REASON

Expert Reply
Tue February 19, 2013

The carboxylate ion is more stable than the phenoxide ion. This is because in the phenoxide ion, the negative charge resides on one electronegative oxygen atom and the lesser electronegative carbon atoms. Consequently their contribution towards resonance stabilisation of the phenoxide ion is less. 

 

On the other hand in case of carboxylate ion, the negative charge is very well accommodated between two electronegative oxygen atoms and hence the carboxylate ion is more resonance stabilized than the phenoxide ions. 

 

 

As a result of more stability of the carboxylate ion than the phenoxide ion, the carboxylic acids are stronger than phenols. 

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