Question

The $pK_a$ of acetic acid is lower than that of phenol. Phenoxide ion is more resonance stabilised.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (C)

If assertion is true but reason is false

Answer 2

Low value of $p K_{a}$ corresponds to more acidic compound. Acetic acid $\left( p K_{a}=4.0\right)$ is more acidic than phenol $\left( p K_{a}=9.0\right)$. It is due to the fact that carboxylate ion is more stabilised due to resonance.