Which of the following compounds can yield only one monochlorinated product upon free radical chlorination?

Options

A. 2,2-Dimethylopropane
B. 2-Methylpropane
C. 2-Methybutane
D. n-Butane

Explanation

To determine which of the given compounds can yield only one monochlorinated product upon free radical chlorination, we need to analyze each compound based on the types of hydrogen atoms present. Monochlorination refers to the substitution of one hydrogen atom with a chlorine atom in the presence of chlorine radicals.

### Step-by-Step Solution:

1. **Understand Monochlorination**:
- Monochlorination is the process where one hydrogen atom in an alkane is replaced by a chlorine atom. The outcome depends on the types of hydrogen atoms present (primary, secondary, or tertiary).

2. **Analyze the First Compound: 2,2-Dimethylpropane (C5H12)**:
- Structure:
```
CH3
|
CH3-C-CH3
|
CH3
```
- All hydrogen atoms are equivalent because they are attached to the same carbon (tertiary carbon).
- **Result**: Only one type of hydrogen leads to one monochlorinated product (e.g., 2,2-dimethyl-2-chloropropane).

3. **Analyze the Second Compound: 2-Methylpropane (C5H12)**:
- Structure:
```
CH3
|
CH3-CH-CH2-CH3
```
- There are primary and secondary hydrogens. Chlorination can occur at different positions leading to multiple products.
- **Result**: More than one monochlorinated product.

4. **Analyze the Third Compound: 2-Methylbutane (C6H14)**:
- Structure:
```
CH3
|
CH3-CH-CH2-CH3
```
- Similar to the previous compound, there are different types of hydrogens (primary and secondary).
- **Result**: More than one monochlorinated product.

5. **Analyze the Fourth Compound: n-Butane (C4H10)**:
- Structure:
```
CH3-CH2-CH2-CH3
```
- This compound has primary hydrogens at both ends and secondary hydrogens in the middle, leading to multiple products.
- **Result**: More than one monochlorinated product.

6. **Conclusion**:
- The only compound that yields only one monochlorinated product upon free radical chlorination is **2,2-dimethylpropane**.

### Final Answer:
**The correct answer is 2,2-dimethylpropane.**