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

Options

A. 8
B. 2
C. 4
D. 6

Answer

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

### Step 1: Understand the structure of 2-methylbutane
2-methylbutane has the following structure:
```
CH3
|
CH3-CH-CH2-CH3
```
This can also be represented as:
```
CH3
|
CH2-CH-CH3
|
CH3
```
Here, the second carbon has a methyl group attached to it.

### Step 2: Identify the hydrogens that can be replaced by chlorine
In monochlorination, we can replace one hydrogen atom with a chlorine atom. The hydrogens are located on the following carbons:
- Carbon 1: CH3 (3 hydrogens)
- Carbon 2: CH (1 hydrogen, 1 methyl, 1 ethyl)
- Carbon 3: CH2 (2 hydrogens)
- Carbon 4: CH3 (3 hydrogens)

### Step 3: List the possible monochlorination products
1. **Chlorination at Carbon 1**:
- Product: CH2Cl-CH(CH3)-CH2-CH3 (no chiral center)

2. **Chlorination at Carbon 2**:
- Product: CH3-CH(Cl)-CH2-CH3 (chiral center)

3. **Chlorination at Carbon 3**:
- Product: CH3-CH(CH3)-CH(Cl)-CH3 (chiral center)

4. **Chlorination at Carbon 4**:
- Product: CH3-CH2-CH(CH3)-CH2Cl (no chiral center)

### Step 4: Identify chiral centers
A chiral center is a carbon atom that has four different substituents.
- **Product 1**: No chiral center (two identical hydrogens).
- **Product 2**: Chiral center (one hydrogen, one methyl, one ethyl, one chlorine).
- **Product 3**: Chiral center (one hydrogen, one methyl, one isopropyl, one chlorine).
- **Product 4**: No chiral center (two identical hydrogens).

### Step 5: Count the chiral compounds
From our analysis:
- **Chiral compounds**: Product 2 and Product 3.
- **Total chiral compounds**: 2.

### Final Answer
The total number of chiral compounds possible from the monochlorination of 2-methylbutane is **2**.

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