How many monochlorobutanes will be obtained on chlorination of n-butane?

Options

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

Explanation

To determine how many monochlorobutanes can be obtained from the chlorination of n-butane, we can follow these steps:

### Step 1: Understand the Structure of n-Butane
n-Butane has the molecular formula C4H10 and its structure can be represented as:
\[ \text{CH}_3 - \text{CH}_2 - \text{CH}_2 - \text{CH}_3 \]

### Step 2: Identify the Hydrogen Atoms
In n-butane, there are:
- 3 terminal hydrogen atoms (attached to the two CH3 groups)
- 6 hydrogen atoms attached to the three CH2 groups

### Step 3: Chlorination Process
During chlorination, one hydrogen atom is replaced by a chlorine atom (Cl). This can occur at different positions in the n-butane molecule.

### Step 4: Determine Possible Monochlorobutane Products
1. **Chlorination at Terminal Carbons (CH3 groups)**:
- If we replace one of the terminal hydrogen atoms from the CH3 group, we will get:
\[ \text{CH}_2\text{Cl} - \text{CH}_2 - \text{CH}_2 - \text{CH}_3 \]
- This product is called **1-chlorobutane**.

2. **Chlorination at Internal Carbons (CH2 groups)**:
- If we replace one of the hydrogen atoms from the first CH2 group, we will get:
\[ \text{CH}_3 - \text{CHCl} - \text{CH}_2 - \text{CH}_3 \]
- This product is called **2-chlorobutane**.

### Step 5: Identify Unique Products
- The chlorination at the terminal CH3 groups gives the same product regardless of which terminal hydrogen is replaced.
- The chlorination at the internal CH2 groups also gives the same product regardless of which internal hydrogen is replaced.

### Conclusion
Thus, the two unique monochlorobutane products obtained from the chlorination of n-butane are:
1. 1-chlorobutane
2. 2-chlorobutane

Therefore, the total number of monochlorobutanes obtained is **2**.

### Final Answer
**2 monochlorobutanes will be obtained on chlorination of n-butane.**

---