Respuesta :

-COOH

An organic acid is an organic compound with acidic properties. The most common organic acids are the carboxylic acids, whose acidity is associated with their carboxyl group –COOH

Answer:

–COOH

Explanation:

The function group of an organic acid is –COOH

For example, acetic acid CH₃COOH  has -COOH functional group.    

-CHO is a functional group called aldehyde.

-OCO is a functional group called ester.