The compound ‘A’ having formula `C_8H_(10)` (aromatic) which gives 1 mononitro substitute and 3 dinitrosubstitute compound is

Options

A. m-xylene
B. p-xylene
C. o-xylene
D. Ethyl benzene

Explanation

To solve the problem, we need to identify the compound 'A' with the formula \( C_8H_{10} \) that is aromatic and gives one mononitro substitution and three dinitro substitution products.

### Step-by-Step Solution:

1. **Identify the Structure**:
The molecular formula \( C_8H_{10} \) indicates that the compound is likely an aromatic hydrocarbon. The degree of unsaturation can be calculated as follows:
\[ \text{Degree of Unsaturation} = \frac{(2C + 2 - H)}{2} = \frac{(2 \times 8 + 2 - 10)}{2} = \frac{(16 + 2 - 10)}{2} = \frac{8}{2} = 4 \]
This indicates that there are 4 rings or double bonds present in the structure, confirming that it is aromatic.

2. **Consider Possible Structures**:
The compound could be a derivative of xylene. Xylene has the formula \( C_8H_{10} \) and exists in three isomeric forms: ortho-xylene, meta-xylene, and para-xylene.

3. **Analyze Substitution Patterns**:
- **Mononitro Substitution**:
When one nitro group is added, the compound can yield one mononitro product. This indicates that the compound must have a symmetrical structure that allows only one distinct position for the nitro group.
- **Dinitro Substitution**:
The compound can yield three different dinitro products. This suggests that there are three distinct positions available for the second nitro group after the first has been added.

4. **Identify the Correct Isomer**:
- **Para-xylene** (1,4-dimethylbenzene) fits this requirement perfectly. When one nitro group is added to para-xylene, it can only go to one of the two methyl groups (yielding one mononitro product).
- For dinitro substitution, the nitro groups can be placed in the following positions:
1. On one methyl group and the para position (1,4-dinitro).
2. On both methyl groups (2,5-dinitro).
3. On one methyl group and one of the hydrogen atoms adjacent to it (3,5-dinitro).

5. **Conclusion**:
The compound 'A' is para-xylene (1,4-dimethylbenzene), which gives rise to one mononitro and three dinitro substitution products.

### Final Answer:
The compound 'A' is **para-xylene (1,4-dimethylbenzene)**.