Which of the following compounds contains both a carboxylic acid $\left({\mathrm{COOH}}^1\right)$ and a phenol $\left({\mathrm{ArOH}}^1\right)$ functional group?

• A. 1-naphthol
• B. Salicylic acid
• C. 2-naphthol
• D.

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the functional groups involved. A carboxylic acid group is represented as \(\mathrm{COOH}\), which consists of a carbonyl (\(\mathrm{C=O}\)) and a hydroxyl (\(\mathrm{-OH}\)) group attached to the same carbon. A phenol group is an aromatic ring directly bonded to a hydroxyl group (\(\mathrm{ArOH}\)).
2. Step 2: Analyze each compound to identify these groups. For 1-naphthol and 2-naphthol, recognize that they are naphthalene derivatives with a hydroxyl group attached to the aromatic system, so they contain a phenol group but no carboxylic acid group.
3. Step 3: Examine salicylic acid, which is a benzene ring substituted with both a hydroxyl group (\(\mathrm{OH}\)) and a carboxylic acid group (\(\mathrm{COOH}\)) on adjacent carbons. This means it contains both the phenol and carboxylic acid functional groups.
4. Step 4: Confirm that the presence of both groups in salicylic acid fits the criteria of the question, while the other compounds only have the phenol group.
5. Step 5: Conclude that the compound containing both a carboxylic acid and a phenol functional group is salicylic acid.