Identify 4 functional group: HO-HO-BENZENE RING-CH2-CH-NH2-C=O-OH

1)carboxylic acid functional group
2)amine functional group
3)alcohol functional group

i only know three is anyone can tell me the last functional group.please

3 answers

Two Alcohols (OH groups), one carboxylic acid (CO2H), and one amine (NH2) equals four.
the benzene ring because it contains double bonds
1. Ester:COO
2. Ammonium salt NH4+ Cl-
3. Aromatic ring