(N/A) The acidity of carboxylic acids is due to the resonance stabilization of the carboxylate ion.
$(i)$ Carboxylic acids are acidic because they can donate a proton to form a carboxylate ion $(RCOO^-)$.
$(a)$ In the carboxylic acid molecule $(RCOOH)$,resonance involves charge separation,which makes the structures less stable.
$(b)$ In the carboxylate ion $(RCOO^-)$,the negative charge is delocalized over two electronegative oxygen atoms through two equivalent resonance structures. This makes the carboxylate ion highly stable.
$(c)$ Since the conjugate base (carboxylate ion) is much more stable than the acid itself,the equilibrium shifts towards the formation of the carboxylate ion,making carboxylic acids acidic.
$(ii)$ Carboxylic acids are more acidic than phenols because:
$(a)$ In the carboxylate ion,the negative charge is delocalized over two electronegative oxygen atoms,which are equivalent. In the phenoxide ion $(C_6H_5O^-)$,the negative charge is delocalized over the carbon atoms of the benzene ring,which are less electronegative than oxygen. Thus,the carboxylate ion is more stable than the phenoxide ion,making carboxylic acids stronger acids than phenols.