Question

Assertion (A): The pKa} of ethanoic acid is lower than that of C1} – CH2} – COOH.
Reason (R): Chlorine shows electron withdrawing (–I) effect which increases the acidic character of C1} – CH2} – COOH.

• A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
• B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
• C. Assertion (A) is true, but Reason (R) is false
• D. Assertion (A) is false, but Reason (R) is true.

Hint:

Electron-withdrawing groups, like chlorine, increase the acidity of carboxylic acids by stabilizing the conjugate base.

Answer 1

The Correct Option is D

Chloroacetic acid (C1} – CH2} – COOH) has a lower pKa} than acetic acid (ethanoic acid), as the electron withdrawing effect of chlorine enhances the acidity. However, the assertion that the pKa} of ethanoic acid is lower is incorrect.