Answer: ketone
Explanation:
Functional groups are specific group of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules.
1. Amides have functional group .
Example: Ethanamide with molecular formula
2. Aldehydes have functional group .
Example: Ethanal with molecular formula
3. Ketones have functional group .
Example: Propanone with molecular formula
4. Esters have functional group .
Example: methyl ethanoate with molecular formula