Propane on dichlorinatin gives......isomers and out of them .....are optically active.

Options

A. `4,1`
B. `3,1`
C. `4,2`
D. `3,2`

Explanation

To solve the question regarding the dichlorination of propane, we will follow these steps:

### Step 1: Understand the Structure of Propane
Propane (C₃H₈) is a straight-chain alkane with three carbon atoms. Its structure can be represented as:
```
H H H
| | |
H--C--C--C--H
| | |
H H H
```

### Step 2: Perform Dichlorination
Dichlorination involves replacing two hydrogen atoms in propane with chlorine atoms. This can happen in several ways, leading to different isomers.

### Step 3: Identify Possible Isomers
1. **1,1-Dichloropropane**: Both chlorine atoms are attached to the first carbon.
- Structure:
```
Cl Cl
| |
H--C--C--C--H
| |
H H
```

2. **1,2-Dichloropropane**: One chlorine atom on the first carbon and one on the second carbon.
- Structure:
```
Cl H
| |
H--C--C--C--H
| |
H Cl
```

3. **1,3-Dichloropropane**: One chlorine atom on the first carbon and one on the third carbon.
- Structure:
```
Cl H
| |
H--C--C--C--H
| |
H Cl
```

4. **2,2-Dichloropropane**: Both chlorine atoms are attached to the second carbon.
- Structure:
```
H Cl
| |
H--C--C--C--H
| |
Cl H
```

### Step 4: Count the Total Isomers
From the above structures, we can see that there are a total of **4 isomers** formed during the dichlorination of propane.

### Step 5: Identify Optically Active Isomers
An optically active compound has a chiral center, which means it has a carbon atom attached to four different groups.

- **1,1-Dichloropropane**: Not optically active (no chiral center).
- **1,2-Dichloropropane**: Not optically active (no chiral center).
- **1,3-Dichloropropane**: Not optically active (no chiral center).
- **2,2-Dichloropropane**: **Optically active** (the second carbon is a chiral center).

### Conclusion
Thus, the answer to the question is that propane on dichlorination gives **4 isomers**, and out of them, **1 is optically active**.

### Final Answer
**4 isomers and 1 optically active.**

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