Which of the following are used as chain transfer agents?

Options

A. `CCl_(4)`
B. `CBr_(4)`
C. Benzoquinone
D. Benzoyl peroxide

Answer

To determine which of the following compounds are used as chain transfer agents, we need to understand what a chain transfer agent is and analyze the given options.

### Step-by-Step Solution:

1. **Definition of Chain Transfer Agents**:
- Chain transfer agents are substances that can terminate the growth of a polymer chain and initiate a new one. They typically contain at least one weak chemical bond that facilitates this transfer reaction.

2. **Common Examples of Chain Transfer Agents**:
- Common chain transfer agents include thiols (like DDM) and halocarbons such as carbon tetrachloride (CCl4) and carbon tetrabromide (CBr4).

3. **Analyzing the Options**:
- **Option 1: CCl4 (Carbon Tetrachloride)**
- This is a halocarbon and is known to act as a chain transfer agent.
- **Conclusion**: This option is correct.

- **Option 2: CBr4 (Carbon Tetrabromide)**
- This is also a halocarbon and is recognized as a chain transfer agent.
- **Conclusion**: This option is correct.

- **Option 3: Benzoquinone**
- This compound does not have the properties of a chain transfer agent and is not commonly used for this purpose.
- **Conclusion**: This option is incorrect.

- **Option 4: Benzoyl Peroxide**
- Benzoyl peroxide is primarily used as an initiator in polymerization reactions, not as a chain transfer agent.
- **Conclusion**: This option is incorrect.

4. **Final Answer**:
- The correct options for chain transfer agents from the given list are CCl4 and CBr4.