Which of the following reagent can convert phenol (PhOH) to anisole `(PhOCH_(3))`?

Options

A. `CHCl_(3)`
B. `CH_(2)N_(2)`
C. `CH_(3)Cl`
D. `HCHO`

Explanation

To convert phenol (PhOH) to anisole (PhOCH₃), we need to identify the appropriate reagent that facilitates this transformation. Let's analyze the options step by step.

### Step-by-Step Solution:

1. **Identify the Structure of Phenol and Anisole**:
- Phenol (PhOH) consists of a hydroxyl group (-OH) attached to a benzene ring.
- Anisole (PhOCH₃) consists of a methoxy group (-OCH₃) attached to a benzene ring.

2. **Determine the Reaction Needed**:
- We need to replace the hydroxyl group (-OH) in phenol with a methoxy group (-OCH₃).

3. **Evaluate the Options**:
- **Option A: CHCl₃ with KOH (Riemer-Tiemann Reaction)**:
- This reaction does not produce anisole; instead, it leads to the formation of substituted phenols, such as benzaldehyde. Therefore, this option is not suitable.

- **Option B: Diazomethane (CH₂N₂)**:
- Diazomethane reacts with phenol to form anisole. The nitrogen gas (N₂) is released, and the methoxy group (-OCH₃) is introduced. This is the correct reagent for the conversion.

- **Option C: CH₃Cl with FeCl₃**:
- This reaction would lead to the formation of cresol (methyl-substituted phenol) through electrophilic aromatic substitution, not anisole. Thus, this option is incorrect.

- **Option D: Aldehyde**:
- Treating phenol with an aldehyde does not yield anisole. This reaction would not replace the -OH group with -OCH₃, so this option is also incorrect.

4. **Conclusion**:
- The only reagent that successfully converts phenol to anisole is diazomethane (CH₂N₂). Therefore, the correct answer is **Option B**.

### Final Answer:
The reagent that can convert phenol to anisole is **diazomethane (CH₂N₂)**.

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