Treatment of sodium salt of phenol with carbon dioxide under pressure brings about substitution of the carboxyl group, -COOH, for hydrogen of the ring. This provides a path of conversion of phenol into hydroxy carboxylic acids. The acids formed are industrially very important compounds and form many useful compounds.
How will you convert the product into aspirin?

Explanation

To convert the product obtained from the treatment of the sodium salt of phenol with carbon dioxide into aspirin, we can follow these steps:

### Step-by-Step Solution:

1. **Formation of Salicylic Acid**:
- Begin with the sodium salt of phenol (C6H5O^- Na^+). When this salt is treated with carbon dioxide (CO2) under high pressure, a reaction occurs that leads to the substitution of a hydrogen atom on the aromatic ring with a carboxyl group (-COOH). This process is known as the Kolbe-Schmitt reaction.
- The product formed is salicylic acid (C6H4(OH)(COOH)).

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