Which of the Following Functional Groups is the Carboxyl Group

Question

Which of the following functional groups is the carboxyl group?
A) -NH2
B) -PO4
C) -COOH
D) -SH
E) -OH

Accepted Answer

The carboxyl group is -COOH, which consists of a carbonyl group (C=O) and a hydroxyl group (-OH) bonded to the same carbon atom. The -NH2 group is an amino group, the -PO4 group is a phosphate group, the -SH group is a sulfhydryl group, and the -OH group is a hydroxyl group.