Which of the following aromatic acids is most acidic?

Options

A.
B.
C.
D.

Answer

B

Explanation

It is due to ortho-effect i.e., ortho sustituted acid is stronger.Benzoic acid is a resonance hybrid, and so the carbonyl group is coplanar with the ring.An o-substitutent tends to prevent this coplanarity . The resonance is diminished( or prevented ) , and so the O atom of the -OH group has a greater positive charge, resulting in increased acid-strength.