Which of the Following Must Be Present in a Carboxylic

Question

Which of the following must be present in a carboxylic acid?
A) a carbonyl group and a hydroxyl group bonded to different carbon atoms
B) a carbonyl group and a hydroxyl group bonded to the same carbon atom
C) two hydroxyl groups bonded to the same carbon atom
D) two carbonyl groups bonded to the same carbon atom

Accepted Answer

Carboxylic acids have a carbonyl group (C=O) and a hydroxyl group (-OH) bonded to the same carbon atom, known as the carboxyl group (-COOH). Option A has a carbonyl group and a hydroxyl group, but they are bonded to different carbon atoms, making it an aldehyde or a ketone. Options C and D have multiple hydroxyl or carbonyl groups on the same carbon atom, which is not possible due to the valency of carbon.