The functional group for an organic acid is: - CHO - OCO - CH - COOH

-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.

-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