Which of the following reagent can be used to convert benzene diazonium chloride to phenol?

Options

A. `H_3PO_4`
B. `dil,H_2SO_4`
C. `H_2O`
D. all of these

Answer

To convert benzene diazonium chloride to phenol, we can use several reagents. Let's break down the steps involved in this conversion:

### Step-by-Step Solution:

1. **Identify Benzene Diazonium Chloride**:
Benzene diazonium chloride is represented as C6H5-N2^+Cl^-. It consists of a benzene ring (C6H5) with a diazonium group (N2^+) and a chloride ion (Cl^-).

2. **Reagents for Conversion**:
The common reagents that can be used to convert benzene diazonium chloride to phenol include:
- **Dilute H2SO4 (Sulfuric Acid)**: This reagent can facilitate the release of nitrogen gas (N2) and lead to the formation of phenol.
- **H3PO4 (Phosphoric Acid)**: Similar to sulfuric acid, phosphoric acid can also promote the reaction and result in the formation of phenol.
- **Water (H2O)**: Water can also be used as a reagent since it contains H^+ and OH^- ions, which can participate in the reaction.

3. **Mechanism of Reaction**:
- When benzene diazonium chloride reacts with dilute H2SO4 or H3PO4, the diazonium group (N2^+) is released as nitrogen gas (N2), which is unstable and escapes from the solution.
- The remaining carbon atom in the benzene ring becomes positively charged after the loss of the diazonium group.
- The hydroxide ion (OH^-) from the acid or water attacks the positively charged carbon, leading to the formation of phenol (C6H5OH).

4. **Final Product**:
The final product of the reaction is phenol (C6H5OH), along with the release of nitrogen gas (N2) and possibly other byproducts depending on the reagent used.

5. **Conclusion**:
Therefore, the reagents that can be used to convert benzene diazonium chloride to phenol are:
- Dilute H2SO4
- H3PO4
- H2O

### Final Answer:
All of the above reagents (Dilute H2SO4, H3PO4, and H2O) can be used to convert benzene diazonium chloride to phenol.

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