CHEMISTRY · Multi-part · A Level · Chemistry · Acids and bases · Acids and bases
Problem
Two monoprotic carboxylic acids are shown below.
• Chloroacetic acid: ClCH2COOH
• Propanoic acid: CH3CH2COOH
Assume standard conditions (25 °C, aqueous solution).
(1) Part 1: Identify which of the two acids is expected to have the larger Ka value.
(2) Part 2: Justify your answer in part (a) by discussing how the molecular structures influence the stability of each conjugate base.
(3) Part 3: For the conjugate bases ClCH2COO− and CH3CH2COO−, state which is the weaker base and explain your reasoning in terms of electron distribution.
(4) Part 4: Predict qualitatively how the acid strength would change if a second chlorine atom were substituted on the β-carbon (Cl2CHCOOH). Explain your prediction.