The major product obtained in the photo catalyzed bromination of 2-methylbutane is :

Options

A. 1-bromo-2-methylbutane
B. 1-bromo-3-methylbutane
C. 2-bromo-3-methylbutane
D. 2-bromo-2-methylbutane

Answer

To determine the major product obtained in the photocatalyzed bromination of 2-methylbutane, we will follow these steps:

### Step 1: Identify the Structure of 2-Methylbutane
2-methylbutane is an alkane with the following structure:
- It has a four-carbon chain (butane) with a methyl group (−CH₃) attached to the second carbon.

### Step 2: Understand the Mechanism of Photocatalyzed Bromination
Photocatalyzed bromination occurs via a free radical mechanism. This involves the following steps:
1. **Initiation**: Bromine (Br₂) is dissociated into two bromine radicals (Br•) under UV light.
2. **Propagation**: The bromine radical abstracts a hydrogen atom from 2-methylbutane, forming a carbon radical.
3. **Termination**: The carbon radical reacts with another bromine radical to form the brominated product.

### Step 3: Determine the Stability of the Radicals
When bromination occurs, the hydrogen atoms can be abstracted from different positions:
- **Primary Radicals**: Formed by removing a hydrogen from the terminal carbon (least stable).
- **Secondary Radicals**: Formed by removing a hydrogen from the second carbon (more stable).
- **Tertiary Radicals**: Formed by removing a hydrogen from the third carbon (most stable).

In 2-methylbutane, the most stable radical that can form is a tertiary radical, which occurs when a hydrogen is abstracted from the second carbon (C-2), leading to the formation of a tertiary radical at C-2.

### Step 4: Identify the Major Product
The tertiary radical formed will then react with a bromine radical to yield the major product:
- The reaction of the tertiary radical with Br• will produce **2-bromo-2-methylbutane**.

### Conclusion
The major product obtained in the photocatalyzed bromination of 2-methylbutane is **2-bromo-2-methylbutane**.

### Final Answer
**2-bromo-2-methylbutane** (Option 4).

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