How many alkenes can be hydrogenated to give an alkane with molecular formula C4H10 which give three monochloro derivative on monochlorination.

Explanation

To solve the problem, we need to determine how many different alkenes can be hydrogenated to produce an alkane with the molecular formula C4H10, which can also yield three monochloro derivatives upon monochlorination.

### Step-by-Step Solution:

1. **Identify the Alkane**:
The molecular formula C4H10 corresponds to an alkane. The structure of the alkane can be represented as:
- CH3-CH2-CH2-CH3 (butane).

2. **Determine the Alkene Structures**:
To find the alkenes that can be hydrogenated to form butane, we need to consider the possible alkenes with the formula C4H8 (since hydrogenation adds 2 hydrogen atoms).

3. **List Possible Alkenes**:
The possible alkenes that can be formed from C4H8 are:
- 1-butene: CH2=CH-CH2-CH3
- 2-butene: CH3-CH=CH-CH3 (this can exist as cis and trans isomers)
- Isobutylene (2-methylpropene): CH2=C(CH3)-CH3

4. **Count the Unique Alkenes**:
- 1-butene (1 alkene)
- 2-butene (cis and trans count as one alkene, but we will consider them as two for monochlorination)
- Isobutylene (1 alkene)

This gives us a total of 3 unique alkenes:
- 1-butene
- 2-butene (cis and trans)
- Isobutylene

5. **Monochlorination**:
Each of these alkenes can yield three different monochloro derivatives:
- 1-butene can yield 2 monochloro derivatives.
- 2-butene (cis and trans) can yield 3 monochloro derivatives.
- Isobutylene can yield 2 monochloro derivatives.

6. **Final Count**:
Therefore, the total number of alkenes that can be hydrogenated to give C4H10 and yield three monochloro derivatives is 3.

### Final Answer:
**There are 3 alkenes that can be hydrogenated to give C4H10 and yield three monochloro derivatives.**