Which of the following are used as free radical chain initiators?

Options

A. Benzoyl preoxide
B. `t`-Butyl peroxide
C. `CCl_(4)`
D. Benzoquinone

Answer

To determine which of the given options are used as free radical chain initiators, we can follow these steps:

### Step 1: Understand Free Radical Chain Reactions
Free radical chain reactions involve three distinct phases: initiation, propagation, and termination. In the initiation phase, free radicals are generated, which then propagate the reaction.

**Hint:** Recall the three phases of a radical chain reaction: initiation, propagation, and termination.

### Step 2: Identify Radical Initiators
Radical initiators are substances that can produce free radicals under mild conditions. They typically possess weak bonds that can easily dissociate to form radicals. Common examples of radical initiators include:
- Azo compounds
- Organic peroxides (e.g., benzoyl peroxide, tert-butyl peroxide)
- Inorganic peroxides

**Hint:** Look for substances that can easily break down to form free radicals.

### Step 3: Analyze the Given Options
Now, let's evaluate the options provided:

1. **Benzoyl peroxide**: This is a well-known radical initiator used in polymer synthesis. **(Correct)**
2. **Tert-butyl peroxide**: This is also a radical initiator commonly used in various reactions. **(Correct)**
3. **Cl4 (Carbon tetrachloride)**: This compound does not act as a radical initiator. **(Incorrect)**
4. **Benzoquinone**: This compound is not typically used as a radical initiator. **(Incorrect)**

**Hint:** Check if the compounds listed are known for their ability to generate free radicals.

### Step 4: Conclusion
Based on the analysis, the correct options that are used as free radical chain initiators are:
- **Benzoyl peroxide**
- **Tert-butyl peroxide**

**Final Answer:** Benzoyl peroxide and tert-butyl peroxide are used as free radical chain initiators.