The number of isomers of the aromatic compound `C_8H_(10)` is :

Options

A. 3
B. 4
C. 2
D. 5

Answer

To determine the number of isomers for the aromatic compound \( C_8H_{10} \), we can follow these steps:

### Step 1: Identify the Structure
The compound \( C_8H_{10} \) indicates that we have a total of 8 carbon atoms and 10 hydrogen atoms. Since it is an aromatic compound, we can start with a benzene ring, which has 6 carbon atoms.

### Step 2: Add Additional Carbons
After forming the benzene ring (C6H6), we have 2 more carbon atoms to include in our structure. These can be added as substituents on the benzene ring.

### Step 3: Consider Possible Substituents
The two additional carbon atoms can be added in various ways:
1. As a straight chain (ethyl group).
2. As two methyl groups.

### Step 4: Draw Isomers
1. **Ethylbenzene**: One of the carbon atoms can be attached as an ethyl group (C2H5) to the benzene ring. This gives us one isomer.
2. **Dimethylbenzene Isomers**: The two carbon atoms can also be added as two methyl groups (CH3). The positions of these methyl groups can vary:
- **Ortho (1,2-dimethylbenzene)**: Both methyl groups are on adjacent carbons.
- **Meta (1,3-dimethylbenzene)**: Methyl groups are separated by one carbon.
- **Para (1,4-dimethylbenzene)**: Methyl groups are opposite each other on the benzene ring.

### Step 5: Count the Isomers
Now, we can summarize the isomers:
1. Ethylbenzene (1 isomer)
2. 1,2-Dimethylbenzene (ortho) (1 isomer)
3. 1,3-Dimethylbenzene (meta) (1 isomer)
4. 1,4-Dimethylbenzene (para) (1 isomer)

### Conclusion
Thus, the total number of isomers for the compound \( C_8H_{10} \) is 4.

### Final Answer
The number of isomers of the aromatic compound \( C_8H_{10} \) is **4**.

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