Phenol, `C_(6)H_(5)OH` when it first reacts with concentrated sulphuric acid, forms Y. The compound, Y is reacted with concentrated nitric acid to form Z. Identify Y and Z and explain why phenol is not converted commercially to Z by reacting it with conc. `HNO_(3)`.

Explanation

To solve the problem, we need to identify the compounds Y and Z formed during the reactions of phenol with concentrated sulfuric acid and concentrated nitric acid, respectively, and explain why phenol is not converted commercially to Z.

### Step-by-Step Solution:

1. **Identify the Reaction of Phenol with Concentrated Sulfuric Acid**:
- When phenol (C₆H₅OH) reacts with concentrated sulfuric acid (H₂SO₄), it undergoes sulfonation. The hydroxyl group (–OH) on phenol activates the aromatic ring, making it more reactive towards electrophilic substitution.
- The electrophile generated in this reaction is the bisulfate ion (HSO₃⁻), which leads to the formation of phenyl sulfate (Y).
- **Y = C₆H₅OSO₃H** (Phenyl hydrogen sulfate)
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