Carboxylate resonance hybrid.

Carboxylic acids are classified as weak acids. Typically, the pK_a's of a carboxylic acid is approximately 5. Even though they are categorized as 'weak' acids, having a pK_a's greater than 1, carboxylic acids are much stronger acids than alcohols. This is because the product of ionization is a resonance stabilized carboxylate ion, so the acid-base equilibrium is shifted to favor ionization when compared to alcohols.