Xylenes on oxidation with acidic `KMnO_4` gives

Options

A. Terphthalic acid
B. Phthalic acid
C. Isophthalic acid
D. All of these

Answer

To solve the question regarding the oxidation of xylenes with acidic KMnO₄, we will follow these steps:

### Step 1: Identify the Structure of Xylenes
Xylenes are dimethyl-substituted benzenes, and there are three isomers:
- **Ortho-xylene**: Two methyl groups on adjacent carbon atoms (1,2-dimethylbenzene).
- **Meta-xylene**: Methyl groups on carbon atoms separated by one carbon atom (1,3-dimethylbenzene).
- **Para-xylene**: Methyl groups on opposite carbon atoms (1,4-dimethylbenzene).

### Step 2: Understand the Oxidation Reaction
When xylenes are oxidized, particularly with a strong oxidizing agent like acidic KMnO₄, the methyl groups (-CH₃) are oxidized to carboxylic acid groups (-COOH).

### Step 3: Determine the Products of Oxidation
- **Ortho-xylene**: Upon oxidation, it forms **isophthalic acid** (1,3-benzenedicarboxylic acid) where the carboxylic acid groups are at the 1 and 3 positions.
- **Meta-xylene**: Oxidation leads to the formation of **isothalic acid** (1,2-benzenedicarboxylic acid) where the carboxylic acid groups are at the 1 and 2 positions.
- **Para-xylene**: This will yield **phthalic acid** (1,4-benzenedicarboxylic acid) where the carboxylic acid groups are at the 1 and 4 positions.

### Step 4: Summarize the Products
Thus, the oxidation of xylenes with acidic KMnO₄ gives:
- Ortho-xylene → Isophthalic acid
- Meta-xylene → Isothalic acid
- Para-xylene → Phthalic acid

### Final Answer
Xylenes on oxidation with acidic KMnO₄ yield phthalic acid and isothalic acid.

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