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 follow these steps:

### Step 1: Understanding the Reactants
Benzene diazonium chloride is a compound that contains a diazonium group (-N₂⁺) attached to a benzene ring. It is formed by the reaction of an aromatic amine (like aniline) with nitrous acid (HNO₂) at low temperatures.

### Step 2: Identifying the Reaction Conditions
To convert benzene diazonium chloride to phenol, we need to perform hydrolysis. Hydrolysis involves the reaction of the diazonium compound with water, which can be facilitated by heating.

### Step 3: Choosing the Reagent
The reagents that can be used for the hydrolysis of benzene diazonium chloride include:
- Water (H₂O)
- Dilute sulfuric acid (H₂SO₄)
- Phosphoric acid (H₃PO₄)

All of these reagents can effectively hydrolyze benzene diazonium chloride to yield phenol.

### Step 4: Performing the Reaction
When benzene diazonium chloride is treated with water or dilute sulfuric acid, the diazonium group is replaced by a hydroxyl group (-OH), resulting in the formation of phenol.

### Final Answer
Thus, the reagents that can be used to convert benzene diazonium chloride to phenol are:
- Water (H₂O)
- Dilute sulfuric acid (H₂SO₄)
- Phosphoric acid (H₃PO₄)