R-COOH represents which functional group?

R-COOH represents which functional group?

• A. Alcohol
• B. Carboxylic acid
• C. Aldehyde
• D. Ketone

Answer: (B)

R-COOH is the carboxyl group: a carbon atom double-bonded to oxygen and also single-bonded to a hydroxyl group, with the rest of the molecule attached to that carbon (the R). This specific arrangement—C=O with an attached OH on the same carbon—is what defines carboxylic acids. Alcohols have only an –OH, aldehydes have a carbonyl on a carbon with a hydrogen and no attached –OH, and ketones have a carbonyl bonded to two carbon groups with no attached –OH. So the presence of both the carbonyl and the hydroxyl on the same carbon makes it a carboxylic acid.

R-COOH is the carboxyl group: a carbon atom double-bonded to oxygen and also single-bonded to a hydroxyl group, with the rest of the molecule attached to that carbon (the R). This specific arrangement—C=O with an attached OH on the same carbon—is what defines carboxylic acids. Alcohols have only an –OH, aldehydes have a carbonyl on a carbon with a hydrogen and no attached –OH, and ketones have a carbonyl bonded to two carbon groups with no attached –OH. So the presence of both the carbonyl and the hydroxyl on the same carbon makes it a carboxylic acid.