Which one of the following is a non-benzenoid aromatic compound

Options

A. Aniline
B. Benzoic acid
C. Naphthalene
D. Tropolone

Explanation

To determine which of the given compounds is a non-benzenoid aromatic compound, we will analyze each option step by step.

### Step 1: Identify the Compounds
The compounds mentioned are:
1. Aniline
2. Benzoic acid
3. Naphthalene
4. Tropon (or Tropolone)

### Step 2: Classify Each Compound
We need to classify each compound as either a benzenoid or non-benzenoid aromatic compound.

- **Aniline**:
- Aniline is a derivative of benzene where one hydrogen atom is replaced by an amino group (-NH2).
- Since it is derived from benzene, it is classified as a benzenoid aromatic compound.

- **Benzoic Acid**:
- Benzoic acid is another derivative of benzene, where one hydrogen is replaced by a carboxylic acid group (-COOH).
- This compound is also classified as a benzenoid aromatic compound.

- **Naphthalene**:
- Naphthalene consists of two fused benzene rings.
- It is also classified as a benzenoid aromatic compound.

- **Tropon (or Tropolone)**:
- Tropon is a cyclic compound that does not contain a benzene ring structure but has a structure that allows for aromaticity due to its conjugated pi system.
- It has 6 pi electrons and satisfies Huckel's rule (4n + 2, where n = 1) for aromaticity, but it is not derived from benzene.

### Step 3: Conclusion
Among the compounds listed, **Tropon** is the only non-benzenoid aromatic compound.

### Final Answer
The non-benzenoid aromatic compound is **Tropon**.

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