Phenol can be prepared by

Options

A. Hydrolysis of chlorobenzene with aqueous KOH solution.
B. Heating sodium salicylate with `(NaOH+CaO)`.
C. Reacting cumene hydroperoxide with dil. `H_(2)SO_(4)`.
D. Heating benzediaznium chloride with dil. `H_(2)SO_(4)`.

Explanation

To prepare phenol, we can consider several methods. Here’s a step-by-step breakdown of the different options available for the preparation of phenol:

### Step 1: Hydrolysis of Chlorobenzene
- **Explanation**: Chlorobenzene (C6H5Cl) does not directly yield phenol (C6H5OH) upon hydrolysis with aqueous KOH under normal conditions. For phenol to be produced, specific conditions such as high temperature and pressure, or the presence of a catalyst, are required.
- **Conclusion**: This method is not a straightforward or preferable route for phenol synthesis.

### Step 2: Decarboxylation of Sodium Salicylate
- **Explanation**: Sodium salicylate (C7H5NaO3) can be treated with soda lime (a mixture of NaOH and CaO) to undergo decarboxylation. This reaction removes a carbon dioxide molecule, leading to the formation of phenol.
- **Conclusion**: This method is a valid and effective way to prepare phenol.

### Step 3: Hydrolysis of Cumene Hydroperoxide
- **Explanation**: Cumene hydroperoxide (C6H5C(CH3)2OOH) can be hydrolyzed in the presence of dilute sulfuric acid to yield phenol and acetone. This reaction is a well-known industrial method for producing phenol.
- **Conclusion**: This method is also a valid route for the preparation of phenol.

### Step 4: Reaction of Benzene Diazonium Chloride with Water
- **Explanation**: Benzene diazonium chloride (C6H5N2Cl) can react with water in the presence of dilute sulfuric acid to produce phenol. This reaction is known as hydrolysis of diazonium salts.
- **Conclusion**: This method is another effective way to prepare phenol.

### Final Conclusion:
- Among the options discussed, the first option (hydrolysis of chlorobenzene with aqueous KOH) is not a suitable method for preparing phenol. The other three methods (decarboxylation of sodium salicylate, hydrolysis of cumene hydroperoxide, and hydrolysis of benzene diazonium chloride) are valid and effective routes for the synthesis of phenol.