The normal range for the carbonyl group of a carboxylic acid in the IR spectrum is 1725 - 1700 cm-1. Why is the carbonyl group of benzoic acid appear at 1696 cm-1?
a. The carbonyl group is in conjugation with the aromatic ring.
b. The oxygen of the carbonyl must be protonated.
c. The carbonyl must be hydrogen bonding with water.
d. That is not the carbonyl peak at 1696 cm-1.