Question

Which statement best explains why 'A' is more acidic than B ?

• A. The larger size of ketone group helps to stabilise the conjugate base.
• B. The ketone group exert a large inductive effect in conjugate base of A.
• C. The ketone group allows for resonance delocalisation of the charge in conjugate base.
• D. The OH oxygen in A is more electronegative than the OH oxygen in B.

Answer 1

Answer: (C)

The ketone group allows for resonance delocalisation of the charge in conjugate base.

Compound A is more acidic than B because of the delocalisation of the charge in its conjugate base due to resonance in the compound A.

As $CO$ group shows $-M$ effect hence stabilises the conjugate base.