Which of the following molecules is classified as a ketone?

• A. ${\mathrm{CH}}_3\mathrm{CO}{\mathrm{CH}}_3$
• B. ${\mathrm{CH}}_3\mathrm{CH}{2}_2\mathrm{OH}$
• C. ${\mathrm{CH}}_3\mathrm{COOH}$
• D. ${\mathrm{CH}}_3\mathrm{CHO}$

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the functional groups involved. A ketone is characterized by a carbonyl group (C=O) bonded to two carbon atoms. This means the carbonyl carbon is connected to alkyl groups on both sides.
2. Step 2: Examine each given molecule's structure to identify the functional groups present. Look specifically for the carbonyl group and what atoms or groups are attached to it.
3. Step 3: For the molecule represented as \(\mathrm{CH_3COCH_3}\), note that the carbonyl carbon (C=O) is bonded to two methyl groups (\(\mathrm{CH_3}\)), fitting the definition of a ketone.
4. Step 4: For the molecule \(\mathrm{CH_3CH_2OH}\), recognize this as an alcohol because of the hydroxyl group (-OH) attached to an ethyl group, not a ketone.
5. Step 5: For the molecules \(\mathrm{CH_3COOH}\) and \(\mathrm{CH_3CHO}\), identify them as a carboxylic acid and an aldehyde respectively, based on their functional groups, which differ from ketones.