Of the following compounds, whose ozonolysis proves the Kekule structure of benzene?

Options

A. a.Benzene
B. b.Toluene
C. c.o-Xylene
D. d.p-Xylene

Explanation

To determine which compound's ozonolysis proves the Kekulé structure of benzene, we will analyze the ozonolysis of ortho-xylene (C6H4(CH3)2) and its products.

### Step-by-Step Solution:

1. **Identify the Compound**: The compound in question is ortho-xylene, which has the formula C6H4(CH3)2. It consists of a benzene ring with two methyl (CH3) groups attached to adjacent carbon atoms.

2. **Ozonolysis Reaction**: Ozonolysis is a reaction where ozone (O3) is used to cleave double bonds in organic compounds. The reaction typically involves the use of ozone in a solvent (like CH2Cl2) followed by a reducing agent (like zinc and water) to convert the ozonide intermediate into carbonyl compounds.

3. **Draw the Structure of Ortho-Xylene**: The structure of ortho-xylene can be represented as:
```
CH3
|
C6H4 - C - CH3
|
```

4. **Perform Ozonolysis**: When ortho-xylene undergoes ozonolysis, the double bonds in the benzene ring are cleaved. The ozonolysis will produce several carbonyl compounds. The reaction can be summarized as follows:
- The double bonds are cleaved, resulting in the formation of carbonyl (C=O) groups at the positions where the double bonds were.

5. **Identify the Products**: The ozonolysis of ortho-xylene will yield:
- Glyoxal (C2H2O2): This is formed from the cleavage of the benzene ring and is represented as:
```
O=C-CHO
```
- Methylglyoxal (C3H4O2): This is another product formed during the reaction.
- 1,2-Dimethylglyoxal (C4H6O2): This compound is also produced.

6. **Analyze the Product Ratios**: The products formed from the ozonolysis of ortho-xylene can be summarized in a ratio:
- Glyoxal: 3 moles
- Methylglyoxal: 2 moles
- 1,2-Dimethylglyoxal: 1 mole

7. **Conclusion**: The formation of these products in a specific ratio (3:2:1) from the ozonolysis of ortho-xylene supports the existence of resonance structures in benzene, thus proving the Kekulé structure of benzene.

### Final Answer:
The compound whose ozonolysis proves the Kekulé structure of benzene is **ortho-xylene**.

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