A compound `(A)` with molecular formula `C_(5) H_(10)` gives one monochlorination product. Compound `(A)` is:

Options

A.
B.
C.
D.

Explanation

To determine the compound (A) with the molecular formula C₅H₁₀ that gives only one monochlorination product, we need to analyze the possible structures that fit this molecular formula and their reactivity towards chlorination.

### Step-by-Step Solution:

1. **Identify the Molecular Formula**: The molecular formula given is C₅H₁₀. This indicates that the compound is likely an alkene or a cycloalkane since it has fewer hydrogens than the corresponding alkane (C₅H₁₂).

2. **Consider Possible Structures**:
- The possible structures for C₅H₁₀ include:
- Pentene (linear alkene)
- 2-Methylbutene (branched alkene)
- Cyclopentane (cyclic compound)
- 1-Pentene (linear alkene)
- 2-Pentene (branched alkene)

3. **Analyze Monochlorination**:
- Monochlorination refers to the substitution reaction where one hydrogen atom is replaced by a chlorine atom.
- For a compound to yield only one monochlorination product, it must have identical hydrogen atoms at the position where chlorination can occur.

4. **Evaluate Each Structure**:
- **Pentene**: Has multiple positions for chlorination, leading to multiple products.
- **2-Methylbutene**: Also has multiple positions for chlorination, leading to multiple products.
- **Cyclopentane**: All hydrogen atoms are equivalent, leading to only one product upon chlorination.
- **1-Pentene**: Similar to pentene, multiple products can be formed.
- **2-Pentene**: Similar to 2-methylbutene, multiple products can be formed.

5. **Conclusion**: The only structure that gives one monochlorination product is **Cyclopentane**. Therefore, compound (A) is Cyclopentane.

### Final Answer:
Compound (A) is **Cyclopentane**.