`C_(5)H_(10)overset(H_(2)//Ni)rarr(X) overset(Cl_(2)//hv)rarr 3` monochloro structural isomers for compound `C_(5)H_(10)` how many pairs of geometrical isomers are possible

Options

A. 1
B. 2
C. 3
D. None

Answer

To solve the problem, we will follow a systematic approach to determine the number of pairs of geometrical isomers possible for the compound C5H10 after hydrogenation and chlorination reactions.

### Step 1: Identify the structure of C5H10
C5H10 can represent various alkenes. The most common structures include:
- 1-pentene: CH2=CH-CH2-CH2-CH3
- 2-pentene: CH3-CH=CH-CH2-CH3
- 3-pentene: CH3-CH2-CH=CH-CH3
- Cyclopentane: C5H10 (but this is not an alkene)

### Step 2: Hydrogenation of C5H10
When C5H10 is treated with H2 in the presence of a nickel catalyst, it undergoes hydrogenation to form an alkane (C5H12). The alkene structure that will be hydrogenated will determine the geometrical isomers formed.

### Step 3: Identify the possible alkenes and their geometrical isomers
1. **1-pentene**: No geometrical isomers (since there is no double bond).
2. **2-pentene**: This can exist in two forms:
- Cis-2-pentene (both methyl groups on the same side of the double bond)
- Trans-2-pentene (methyl groups on opposite sides)
- Thus, 2-pentene has one pair of geometrical isomers (cis and trans).
3. **3-pentene**: Similar to 2-pentene, it can also exist in two forms:
- Cis-3-pentene
- Trans-3-pentene
- Thus, 3-pentene also has one pair of geometrical isomers (cis and trans).

### Step 4: Count the pairs of geometrical isomers
From the analysis:
- 2-pentene contributes 1 pair of geometrical isomers.
- 3-pentene contributes 1 pair of geometrical isomers.

### Final Count
Thus, the total number of pairs of geometrical isomers for C5H10 after hydrogenation and chlorination is:
- **Total pairs of geometrical isomers = 1 (from 2-pentene) + 1 (from 3-pentene) = 2 pairs.**

### Conclusion
The answer to the question is that there are **2 pairs of geometrical isomers possible** for the compound C5H10.

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