A compound `P(C_(5)H_(6))` gives positive Bayer test and on hydrogentation from a hydrocarbon `B(C_(5)H_(10))` which gives only monochloro product. The compound `'P'` is.

Options

A.
B.
C.
D. all of these

Explanation

To solve the problem, we need to identify the compound P (C₅H₆) based on the information provided about its reactivity and the products formed during hydrogenation and chlorination.

### Step-by-Step Solution:

1. **Understanding the Given Information**:
- Compound P has the formula C₅H₆.
- It gives a positive Baeyer's test, indicating the presence of a double bond or a ring structure.
- Upon hydrogenation, it forms compound B (C₅H₁₀), which yields only one monochloro product upon chlorination.

2. **Analyzing Compound P**:
- Since P gives a positive Baeyer's test, it must contain a double bond or a ring structure.
- The molecular formula C₅H₆ suggests that it is likely an alkene or a cyclic compound.

3. **Considering Possible Structures for P**:
- The possible structures for C₅H₆ could be:
- 1-pentene (linear alkene)
- 2-pentene (could be cis or trans)
- Cyclopentene (cyclic alkene)

4. **Hydrogenation of Compound P**:
- If we consider 1-pentene or 2-pentene, upon hydrogenation, they would yield:
- 1-pentene → Pentane (C₅H₁₀)
- 2-pentene → Pentane (C₅H₁₀)
- If we consider cyclopentene, it would also yield pentane upon hydrogenation.

5. **Chlorination of Compound B (C₅H₁₀)**:
- For 1-pentene, chlorination would yield multiple products (1-chloropentane and 2-chloropentane).
- For 2-pentene, chlorination would also yield multiple products (1-chloropentane, 2-chloropentane, and 3-chloropentane).
- For cyclopentene, chlorination would yield only one product (chlorocyclopentane), since all the hydrogen atoms are equivalent.

6. **Conclusion**:
- Since compound B (C₅H₁₀) gives only one monochloro product, the only suitable structure for compound P (C₅H₆) is cyclopentene.

### Final Answer:
The compound P is **cyclopentene**.