Three monoprotic organic acids—acetic acid (CH3COOH)
CHEMISTRY · Multi-part · A Level · Chemistry · Carboxylic acids and derivatives · Carboxylic acids and derivatives
Problem
Three monoprotic organic acids—acetic acid (CH3COOH), benzoic acid (C6H5COOH), and 3-oxobutanoic acid (CH3COCH2COOH)—are dissolved separately in water at equal molar concentrations. Answer the following questions about their acid–base behavior.
(a) For each acid, draw every important resonance contributor of its conjugate base and indicate the location of the negative charge in each contributor.
(b) Rank the acids from strongest to weakest. Provide a detailed justification that refers explicitly to the resonance contributors you drew in part (a).
(c) An aqueous solution of ammonia is added dropwise to a mixture that contains equal molar amounts of the three acids. Predict which single conjugate base will be present in greatest concentration once equilibrium is established, and explain your reasoning.