Question

Account for the following : Cl – CH₂COOH is a stronger acid than CH₃COOH.

Answer 1

Cl-CH₂COOH is a stronger acid than CH₃COOH :
Substitution of electron withdrawing group on carboxylic acid affect the acidity of the carboxylic acid. Chlorine is a electron withdrawing group and its increase the acidity of carboxylic acids by stabilising the conjugate base due to delocalisation of the negative charge by resonance effects. Chloroacetic acid ( Cl-CH₂COOH) pK_a value is equal to 2.7, while pK_a value of acetic acid (CH₃COOH) is equal to 4.7.

Answer 2

Monochloroacetic acid is stronger than acetic acid. This is due to –Cl as a – I group.