Toluene may be prepared by :

Options

A. Toluic acid
B. Cresol
C. Toluene sulphonic acid
D. All the above

Explanation

To prepare toluene, we can utilize several methods. Below is a step-by-step explanation of the preparation methods mentioned in the video transcript.

### Step-by-Step Solution:

1. **Preparation from Toluic Acid**:
- Toluic acid can be represented in different forms (ortho, meta, or para). For example, let's take ortho-toluic acid (C6H4(CH3)COOH).
- When toluic acid reacts with sodium hydroxide (NaOH), it forms sodium toluate (C6H4(CH3)COONa).
- This sodium toluate is then treated with soda lime (a mixture of NaOH and CaO) and heated.
- The reaction leads to the decarboxylation of sodium toluate, resulting in the formation of toluene (C6H5CH3) and sodium carbonate (Na2CO3) as a byproduct.

2. **Preparation from Cresol**:
- Cresol (C7H8O) can also be used, which contains a hydroxyl (OH) group attached to a benzene ring.
- When cresol is distilled with zinc dust (Zn), it undergoes reduction.
- The reaction produces toluene (C6H5CH3) and zinc oxide (ZnO) as a byproduct.

3. **Preparation from Toluene Sulfonic Acid**:
- Toluene sulfonic acid (C7H8O3S) can be used as a precursor.
- When toluene sulfonic acid is treated with superheated steam or boiled with hydrochloric acid (HCl), it undergoes hydrolysis.
- This reaction results in the formation of toluene (C6H5CH3) and sulfuric acid (H2SO4) as a byproduct.

### Conclusion:
All the methods mentioned above can be utilized to prepare toluene. Therefore, the answer to the question is that toluene may be prepared by all of the above methods.

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