Which of the following acid on decarboxylation does not from an aromatic hydrocarbon

Options

A. Phenylacetic acid
B. Salicylic acid
C. Ortho toluic acid
D. Benzoic acid

Answer

To determine which acid does not form an aromatic hydrocarbon upon decarboxylation, we will analyze each of the given acids step by step.

### Step 1: Understand Decarboxylation
Decarboxylation is the process of removing a carboxyl group (-COOH) from a compound, resulting in the release of carbon dioxide (CO2). This reaction typically requires a strong base, such as soda lime (a mixture of sodium hydroxide and calcium oxide).

### Step 2: Analyze Each Acid

1. **Phenyl Acetic Acid**:
- Structure: C6H5-CH2-COOH
- Upon decarboxylation, the -COOH group is removed, resulting in the formation of benzene (C6H6) and the release of CO2.
- **Result**: Forms an aromatic hydrocarbon.

2. **Salicylic Acid**:
- Structure: C6H4(OH)COOH (with -OH group on the benzene ring)
- The presence of the -OH group allows for intramolecular hydrogen bonding, which stabilizes the molecule and prevents decarboxylation.
- **Result**: Does not undergo decarboxylation, hence does not form an aromatic hydrocarbon.

3. **Ortho-Toluic Acid**:
- Structure: C6H4(CH3)COOH (with -CH3 group on the benzene ring)
- Upon decarboxylation, the -COOH group is removed, resulting in the formation of a methyl-substituted benzene (C6H5-CH3).
- **Result**: Forms an aromatic hydrocarbon.

4. **Benzoic Acid**:
- Structure: C6H5COOH
- Upon decarboxylation, the -COOH group is removed, resulting in the formation of benzene (C6H6).
- **Result**: Forms an aromatic hydrocarbon.

### Conclusion
After analyzing all the acids, we find that **salicylic acid** does not form an aromatic hydrocarbon upon decarboxylation due to the stabilization from intramolecular hydrogen bonding.

### Final Answer
**Salicylic Acid** is the acid that does not form an aromatic hydrocarbon upon decarboxylation.

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