Step 1: Understanding the Question:
A phenol is a compound where the hydroxyl (\( -OH \)) group is directly attached to an aromatic ring.
Step 2: Detailed Explanation:
Let's analyze the structures in the images:
- Option A: Shows 3-nitrophenol. The \( -OH \) is directly on the benzene ring. It is a phenol.
- Option B: Shows 2-naphthol. Although it's a bicyclic system (naphthalene), the \( -OH \) is directly attached to the aromatic ring. It belongs to the phenol family.
- Option C: Shows 4-bromophenol. The \( -OH \) is directly on the benzene ring. It is a phenol.
- Option D: Shows benzyl alcohol (\( C_{6}H_{5}CH_{2}OH \)). In this molecule, the hydroxyl group is attached to a saturated carbon atom (\( sp^3 \) hybridized), which is then attached to the ring. This is an aromatic alcohol, not a phenol.
Step 3: Final Answer:
Option D (Benzyl alcohol) is not a phenol.