The functional group in alcohol is:

• (A) - COO₋
• (B) - COOH
• (C) - OH
• (D) - CHO

The functional group in alcohol is represented by option (C) - OH. This group is known as a hydroxyl group and is what characterizes alcohols.

Understanding Functional Groups

Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. In the case of alcohols, the presence of the hydroxyl group (-OH) is key.

Comparison of Options

• (A) - COO: This is a carboxylate group, typically found in carboxylic acids and esters.
• (B) - COOH: This is the carboxylic acid functional group, which is different from alcohols.
• (C) - OH: Correct! This is the hydroxyl group, defining alcohols.
• (D) - CHO: This is an aldehyde group, not related to alcohols.

In summary, the correct answer is (C) - OH, which identifies the alcohol functional group.