Which of the following compound has incorrect common name ?

Options

A.
B.
C. `CH_(3)-COOH` acetic acd
D.

Explanation

To determine which of the following compounds has an incorrect common name, we will analyze each compound one by one based on the information provided.

### Step-by-Step Solution:

1. **Identify the Compounds**: We will consider the four compounds mentioned in the question:
- Picric Acid
- Trinitrotoluene
- Acetic Acid
- Phthalic Acid

2. **Analyze Picric Acid**:
- **Structure**: Picric acid is a compound with the formula C6H3N3O7. It has three nitro groups (NO2) and one hydroxyl group (OH).
- **Common Name**: The common name "picric acid" is correct. It is indeed more acidic than benzoic acid.

**Hint**: Check the functional groups and their positions in the structure to confirm the common name.

3. **Analyze Trinitrotoluene (TNT)**:
- **Structure**: Trinitrotoluene has a methyl group (CH3) and three nitro groups attached to the benzene ring.
- **Common Name**: The common name "trinitrotoluene" is correct. It is widely known as TNT and is used as an explosive.

**Hint**: Look for the presence of nitro groups and how they affect the name of the compound.

4. **Analyze Acetic Acid**:
- **Structure**: Acetic acid has the formula CH3COOH and is commonly known as vinegar.
- **Common Name**: The common name "acetic acid" is correct.

**Hint**: Remember that acetic acid is synonymous with vinegar in common usage.

5. **Analyze Phthalic Acid**:
- **Structure**: Phthalic acid has two carboxylic acid groups (COOH) attached to a benzene ring.
- **Common Name**: The compound mentioned in the question is phthalic anhydride, which is derived from phthalic acid through dehydration. Therefore, the name given is incorrect.

**Hint**: Identify if the compound is in its acid form or anhydride form to determine the correct common name.

### Conclusion:
Based on the analysis, the compound with the incorrect common name is **Phthalic Acid**, as it is referred to as phthalic anhydride in the question.

### Final Answer:
The compound with the incorrect common name is **Phthalic Acid**.

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