Which functional group is responsible for the characteristic smell of $\mathrm{esters}$?

• A. $\mathrm{Carboxyl} \mathrm{group}$
• B. $\mathrm{Carbonyl} \mathrm{group}$
• C. $\mathrm{Ester} \mathrm{group}$
• D. $\mathrm{Hydroxyl} \mathrm{group}$

Answer: (C)

Verified step by step guidance

1. Identify the functional groups listed in the problem: carboxyl group, carbonyl group, ester group, and hydroxyl group.
2. Understand the structure of each functional group: the carboxyl group contains a carbon double-bonded to an oxygen and single-bonded to a hydroxyl group (COOH), the carbonyl group contains a carbon double-bonded to an oxygen (C=O), the ester group contains a carbon double-bonded to an oxygen and single-bonded to another oxygen that is bonded to another carbon (COOR), and the hydroxyl group contains an oxygen bonded to a hydrogen (OH).
3. Recall that esters are known for their pleasant, fruity smells, which is a characteristic property of the ester functional group.
4. Recognize that the ester group is responsible for the characteristic smell of esters, as it is the defining functional group in ester compounds.
5. Conclude that the ester group is the correct answer, as it is the functional group responsible for the characteristic smell of esters.