Convert benzence to PhCHO in one step only.

Explanation

To convert benzene (C6H6) to phenyl aldehyde (benzaldehyde, PhCHO) in one step, we can utilize the Gattermann reaction. Here’s the step-by-step solution:

### Step 1: Reaction Setup
- **Reactants**: Benzene (C6H6) is reacted with hydrogen cyanide (HC≡N) in the presence of an acid catalyst and aluminum chloride (AlCl3).
- **Conditions**: The reaction is carried out under acidic conditions to facilitate the formation of the required intermediate.

### Step 2: Formation of the Intermediate
- The benzene ring undergoes electrophilic substitution where the hydrogen atom on the benzene is replaced by a formyl group (CHO).
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