Total number of isomeric molecules obtained on dichlorination of cyclopentane

Explanation

To determine the total number of isomeric molecules obtained from the dichlorination of cyclopentane, we will analyze the possible positions of chlorine atoms on the cyclopentane ring.

### Step-by-Step Solution:

1. **Understanding Cyclopentane Structure**:
Cyclopentane is a five-membered carbon ring with the formula C5H10. Each carbon can potentially have a chlorine atom attached during the dichlorination reaction.

**Hint**: Remember that cyclopentane is a cyclic compound, and the position of chlorine substitution is crucial for isomer formation.

2. **Dichlorination Reaction**:
When cyclopentane reacts with chlorine (Cl2) in the presence of light (or heat), it can undergo substitution reactions where one or more hydrogen atoms are replaced by chlorine atoms.

**Hint**: Consider that each chlorine atom can be added to different carbon atoms in the ring.

3. **Identifying Possible Isomers**:
- **Monochlorination**: First, we can consider the monochlorination of cyclopentane, which will yield one monochloro isomer.
- **Dichlorination**: When two chlorine atoms are added, they can occupy different positions on the ring.

4. **Positioning of Chlorine Atoms**:
- **1,1-Dichlorocyclopentane**: Both chlorine atoms are attached to the same carbon atom.
- **1,2-Dichlorocyclopentane**: Chlorine atoms are attached to adjacent carbon atoms. This can lead to two isomers:
- **Cis Isomer**: Both chlorines are on the same side of the ring.
- **Trans Isomer**: Chlorines are on opposite sides of the ring.
- **1,3-Dichlorocyclopentane**: Chlorines are attached to carbons that are two positions apart. This can also yield two isomers:
- **Cis Isomer**: Both chlorines are on the same side.
- **Trans Isomer**: Chlorines are on opposite sides.

5. **Counting the Isomers**:
- From the analysis, we have:
- 1 isomer from 1,1-dichlorocyclopentane.
- 2 isomers from 1,2-dichlorocyclopentane (cis and trans).
- 2 isomers from 1,3-dichlorocyclopentane (cis and trans).
- Therefore, the total number of isomers is:
- 1 (1,1) + 2 (1,2) + 2 (1,3) = 5 isomers.

6. **Conclusion**:
The total number of isomeric molecules obtained from the dichlorination of cyclopentane is **5**.

### Final Answer:
The total number of isomeric molecules obtained on dichlorination of cyclopentane is **5**.