Question

Assertion: The `pK_(a)` of acetic acid is lower than that of phenol.
Reason : Phenoxide ion is more resonance sabilised.
A. If Both assertion and reason are true reason is the correct explation of the assertion.
B. If Both assertion and reason are true but reason is not the correct explation of the assertion.
C. If assertion is true but reason is false.
D. If assertion is false but reason is true.

Answer 1

Correct Answer - C
Low `pK_(a)` value corresponds to more acidic compound. Acetic acid `(pK_(a) = 4.0)` is more acidic than phenol `(pK_(a) = 9.0)`. It is due to the fact that carboxylate ion is more stabilized due to resonance because its resonating stronating strures are equivalent.