2-Methylpropane on monochlorination under photochemical conditions give

Options

A. 2-chloro-2-methylpropane as major product
B. (1:1) mixture of 1-chloro-2-methylpropane and 2-chloro-2-methylpropane
C. 1-chloro-2-methylpropane as a major product
D. (1:9) mixture of 1-chloro-2-methylpropane and 2-chloro-2-methylpropane

Explanation

To solve the problem of what 2-methylpropane gives upon monochlorination under photochemical conditions, we can follow these steps:

### Step 1: Understand the structure of 2-methylpropane
2-methylpropane, also known as neopentane, has the following structure:

```
CH3
|
CH3-C-CH3
|
CH3
```

### Step 2: Identify the type of reaction
Monochlorination is a substitution reaction where one hydrogen atom in the alkane is replaced by a chlorine atom. This reaction typically occurs under photochemical conditions, which means it requires light to initiate the reaction.

### Step 3: Determine the possible sites for chlorination
In 2-methylpropane, there are two types of hydrogen atoms:
- Primary hydrogens (attached to the terminal carbon atoms)
- Secondary hydrogens (attached to the central carbon atom)

The structure indicates that there are:
- 9 primary hydrogens (3 from each of the three terminal CH3 groups)
- 6 secondary hydrogens (from the central carbon)

### Step 4: Predict the products of monochlorination
When monochlorination occurs, chlorine can replace either a primary or secondary hydrogen. The possible products are:
1. **Chloro-2-methylpropane** (from replacing a secondary hydrogen)
2. **1-Chloro-2-methylpropane** (from replacing a primary hydrogen)

### Step 5: Consider the stability of the intermediates
The stability of the radical intermediates formed during chlorination is crucial:
- The secondary radical (formed by removing a secondary hydrogen) is more stable than the primary radical (formed by removing a primary hydrogen).

Thus, the major product will be the one formed from the more stable secondary radical.

### Step 6: Write the final products
The major product of monochlorination of 2-methylpropane will be **2-chloro-2-methylpropane**, while the minor product will be **1-chloro-2-methylpropane**.

### Final Answer:
Upon monochlorination of 2-methylpropane under photochemical conditions, the major product is **2-chloro-2-methylpropane**, and the minor product is **1-chloro-2-methylpropane**.

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