How many chiral compounds are possible on monochlorination of 2-Methyl butane ?

Options

A. (a) 2
B. (b) 4
C. (c) 6
D. (d) 8

Explanation

To determine how many chiral compounds are possible from the monochlorination of 2-methylbutane, we will follow these steps:

### Step 1: Draw the structure of 2-methylbutane.
2-methylbutane has a four-carbon chain (butane) with a methyl group attached to the second carbon. The structure can be represented as follows:

```
CH3
|
CH3-CH-CH2-CH3
|
CH2
```

### Step 2: Identify the possible chlorination sites.
In 2-methylbutane, we can chlorinate the following carbon atoms:
- Carbon 1 (the terminal carbon)
- Carbon 2 (the carbon with the methyl group)
- Carbon 3 (the carbon adjacent to the carbon with the methyl group)
- Carbon 4 (the terminal carbon on the opposite end)

### Step 3: Analyze the products from chlorination.
1. **Chlorination at Carbon 1**:
- The product will be: CH2Cl-CH(CH3)-CH2-CH3
- Carbon 1 is not chiral because it is attached to two hydrogens.

2. **Chlorination at Carbon 2**:
- The product will be: CH3-CHCl-CH2-CH3
- Carbon 2 is not chiral because it is attached to two methyl groups.

3. **Chlorination at Carbon 3**:
- The product will be: CH3-CH(CH3)-CHCl-CH3
- Carbon 3 is chiral because it is attached to four different groups (Cl, CH3, CH2, and H). This will produce a pair of enantiomers.

4. **Chlorination at Carbon 4**:
- The product will be: CH3-CH(CH3)-CH2-CHCl
- Carbon 4 is not chiral because it is attached to two hydrogens.

### Step 4: Count the chiral compounds.
From the analysis:
- Chlorination at Carbon 1: 0 chiral compounds
- Chlorination at Carbon 2: 0 chiral compounds
- Chlorination at Carbon 3: 1 chiral compound (with 2 enantiomers)
- Chlorination at Carbon 4: 0 chiral compounds

### Step 5: Consider chlorination of the methyl groups.
Chlorination can also occur on the two methyl groups (the two CH3 groups attached to Carbon 2):
- Both will yield the same product: CH3-CH(CH2Cl)-CH2-CH3, which is chiral.

### Conclusion:
- From Carbon 3, we have 2 chiral compounds (enantiomers).
- From chlorination of the methyl groups, we have 2 more chiral compounds.

Thus, the total number of chiral compounds from the monochlorination of 2-methylbutane is **4**.

### Final Answer:
**4 chiral compounds are possible from the monochlorination of 2-methylbutane.**

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