What is Z in the following sequence of reactions?
Phenol`underset("dust")overset(Zn)toX underset("Alhyd. "AlCl_(3))overset(CH_(3)Cl)toY underset(KMnO_(4))overset("Alkaline")toZ` Phe

Options

A. Benzene
B. Toluene
C. Benzldehyde
D. Benzoic acid

Answer

To determine what Z is in the given sequence of reactions starting from phenol, we will analyze each step carefully.

### Step-by-Step Solution:

1. **Starting Material: Phenol**
- The reaction begins with phenol (C6H5OH).

2. **Reaction with Zinc Dust**
- When phenol is treated with zinc dust (Zn), it undergoes reduction to form benzene (C6H6).
- **X = Benzene**

3. **Friedel-Crafts Alkylation**
- The benzene (X) is then treated with chloromethane (CH3Cl) in the presence of anhydrous aluminum chloride (AlCl3), which acts as a Lewis acid.
- This reaction is known as Friedel-Crafts alkylation, where a methyl group (CH3) is added to the benzene ring, resulting in toluene (C6H5CH3).
- **Y = Toluene**

4. **Oxidation with Alkaline KMnO4**
- The toluene (Y) is then subjected to oxidation using alkaline potassium permanganate (KMnO4).
- This oxidizes the methyl group (-CH3) to a carboxylic acid group (-COOH), resulting in benzoic acid (C6H5COOH).
- **Z = Benzoic Acid**

### Conclusion:
- After analyzing each step of the reaction sequence, we find that Z is **benzoic acid**.

### Final Answer:
- **Z = Benzoic Acid (C6H5COOH)**