Which of the following is not a functional group commonly found in organic molecules?

• A. Nitrate group (${\mathrm{NO}}_3-$)
• B. Amino group (${\mathrm{NH}}_2$)
• C. Carboxyl group ($\mathrm{COOH}$)
• D. Hydroxyl group ($\mathrm{OH}$)

Answer: (A)

Verified step by step guidance

1. Identify the functional groups listed in the problem: Nitrate group, Amino group, Carboxyl group, and Hydroxyl group.
2. Understand the definition of a functional group: A functional group is a specific group of atoms within a molecule that is responsible for a characteristic chemical reaction of that molecule.
3. Review common functional groups in organic chemistry: Amino group (\(\text{-NH}_2\)), Carboxyl group (\(\text{-COOH}\)), and Hydroxyl group (\(\text{-OH}\)) are all well-known functional groups.
4. Consider the Nitrate group: The Nitrate group (\(\text{-NO}_3\)) is not typically considered a functional group in organic chemistry, as it is more commonly associated with inorganic chemistry.
5. Conclude that the Nitrate group is not a functional group commonly found in organic molecules, unlike the other options provided.