Which one is phenol ?

Options

A.
B.
C.
D.

Explanation

To determine which structure represents phenol, we need to analyze the given options based on the presence and attachment of the hydroxyl (–OH) group to a benzene ring. Here’s a step-by-step solution:

### Step 1: Understand the Definition of Phenol
Phenol is an aromatic compound that consists of a hydroxyl group (-OH) directly attached to a benzene ring.

**Hint:** Look for structures that have a benzene ring with an –OH group attached.

### Step 2: Analyze the Given Structures
Assuming we have four structures labeled A, B, C, and D, we will evaluate each one to see if it meets the criteria for phenol.

1. **Structure A**: Contains an –OH group and a nitro group (–NO2) attached to a benzene ring.
- Since the –OH group is directly attached to the benzene ring, this structure qualifies as phenol.

2. **Structure B**: Contains an –OH group and an aldehyde group (–CHO).
- The aldehyde group has a higher priority than the –OH group, so this structure is not classified as phenol. It is named 4-hydroxybenzaldehyde.

3. **Structure C**: Contains an –OH group but is attached to a carbon that is not part of the benzene ring.
- This structure is known as phenylmethanol (or benzyl alcohol) and does not qualify as phenol.

4. **Structure D**: Contains both a –CN (nitrile) and an –OH group.
- The –CN group has a higher priority than the –OH group, so this structure is named 3-hydroxybenzene nitrile and is not phenol.

### Step 3: Identify the Correct Structure
From the analysis:
- **Structure A** is the only one that qualifies as phenol because it has the –OH group directly attached to the benzene ring.

**Final Answer:** The structure that represents phenol is **Structure A**.

---