Free radical chlorination of hexane produces how many of monochloro derivatives? (including stereoisomer)

Options

A. 5
B. 7
C. 8
D. 3

Answer

To determine how many monochloro derivatives can be produced from the free radical chlorination of hexane, including stereoisomers, we can follow these steps:

### Step 1: Identify the Structure of Hexane
Hexane (C6H14) has the following structure:
- CH3-CH2-CH2-CH2-CH2-CH3

### Step 2: Identify the Types of Carbons in Hexane
Hexane contains:
- 2 primary carbons (at the ends, CH3 groups)
- 4 secondary carbons (the CH2 groups in the middle)

### Step 3: Determine Possible Chlorination Sites
When chlorinating hexane, chlorine can replace a hydrogen atom at any of the carbon positions:
1. Primary carbon (C1 and C6)
2. Secondary carbons (C2, C3, C4, C5)

### Step 4: Count the Unique Monochloro Products
1. **Chlorination at Primary Carbons (C1 and C6)**:
- Both positions yield the same product: 1-chlorohexane.

2. **Chlorination at Secondary Carbons**:
- Chlorination at C2 gives 2-chlorohexane.
- Chlorination at C3 gives 3-chlorohexane.
- Chlorination at C4 gives 2-chlorohexane (same as C2).
- Chlorination at C5 gives 3-chlorohexane (same as C3).

Thus, the unique monochloro derivatives from chlorination are:
- 1-chlorohexane
- 2-chlorohexane
- 3-chlorohexane

### Step 5: Identify Chiral Centers
- **1-chlorohexane**: No chiral centers (only one product).
- **2-chlorohexane**: Has a chiral center (two different groups on the second carbon), leading to 2 stereoisomers.
- **3-chlorohexane**: Also has a chiral center (two different groups on the third carbon), leading to another 2 stereoisomers.

### Step 6: Calculate Total Monochloro Derivatives Including Stereoisomers
- From 1-chlorohexane: 1 product
- From 2-chlorohexane: 2 stereoisomers
- From 3-chlorohexane: 2 stereoisomers

Total = 1 (from 1-chlorohexane) + 2 (from 2-chlorohexane) + 2 (from 3-chlorohexane) = 5 monochloro derivatives.

### Conclusion
The total number of monochloro derivatives produced from the free radical chlorination of hexane, including stereoisomers, is **5**.

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