How can aromatic aldehydes and ketones be prepared by the following reaction ?
(i) Etard reaction.

Explanation

To prepare aromatic aldehydes and ketones using the Etard reaction, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Starting Material**:
- We start with toluene (C6H5CH3), which is an aromatic hydrocarbon consisting of a benzene ring with a methyl group.

2. **Reagents Required**:
...