Which one of the following reagents is used in the Riemer Tiemann reaction?

Options

A. `"aq. NaOH"+CH_(3)Cl`
B. `"aq. NaOH"+CH_(2)Cl_(2)`
C. `"aq. NaOH"+CHCl_(3)`
D. `"aq. NaOH"+CH_(4)`

Explanation

To answer the question regarding the reagent used in the Riemer-Tiemann reaction, we can break down the solution into the following steps:

### Step-by-Step Solution:

1. **Identify the Reaction**: The Riemer-Tiemann reaction is a chemical reaction that converts phenol into salicylaldehyde.

2. **Determine the Reagents Used**: The key reagents for the Riemer-Tiemann reaction are chloroform (CHCl3) and a strong base, which can be sodium hydroxide (NaOH) or potassium hydroxide (KOH).

3. **Understanding the Mechanism**:
- When phenol reacts with chloroform in the presence of a base, the base abstracts a hydrogen atom from the phenol, leading to the formation of a phenoxide ion.
- The chloroform then undergoes a reaction to form a carbene intermediate.
- This carbene reacts with the phenoxide ion, leading to the formation of an intermediate compound.

4. **Formation of Salicylaldehyde**: Through a series of steps involving the loss of a chloride ion and rearrangement, the final product of the reaction is salicylaldehyde.

5. **Conclusion**: Therefore, the reagents used in the Riemer-Tiemann reaction are chloroform (CHCl3) and a strong base like NaOH or KOH.

### Final Answer:
The reagents used in the Riemer-Tiemann reaction are **CHCl3 (chloroform) and NaOH (sodium hydroxide) or KOH (potassium hydroxide)**.

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