Which of the following functional groups is present in ${\mathrm{CH}}_3-\mathrm{COOH}$?

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

Answer: (A)

Verified step by step guidance

1. Identify the molecular formula given: \(\mathrm{CH_3-COOH}\). This represents a molecule with a methyl group (\(\mathrm{CH_3}\)) attached to a \(\mathrm{COOH}\) group.
2. Recall the structure and characteristics of common functional groups: a carboxylic acid contains the \(\mathrm{-COOH}\) group, a ketone contains a carbonyl group (\(\mathrm{C=O}\)) bonded to two carbon atoms, an alcohol contains a hydroxyl group (\(\mathrm{-OH}\)), and an aldehyde contains a carbonyl group bonded to at least one hydrogen atom.
3. Analyze the \(\mathrm{COOH}\) group in the molecule: it consists of a carbonyl (\(\mathrm{C=O}\)) and a hydroxyl (\(\mathrm{-OH}\)) group attached to the same carbon atom, which is the defining feature of a carboxylic acid.
4. Compare this to the other functional groups: the molecule does not have a ketone structure (carbonyl bonded to two carbons), nor is it just an alcohol (only \(\mathrm{-OH}\)), nor an aldehyde (carbonyl bonded to hydrogen and carbon).
5. Conclude that the functional group present in \(\mathrm{CH_3-COOH}\) is the carboxylic acid group.