Which of the following compounds is used as a refrigerant?

Options

A. Acetone
B. `C Cl_4`
C. `CF_4 `
D. `C Cl_2 F_2`

Explanation

To determine which of the given compounds is used as a refrigerant, we can follow these steps:

### Step 1: Identify the Compounds
The options provided are:
1. Acetone
2. CCl4 (Carbon Tetrachloride)
3. CF4 (Carbon Tetrafluoride)
4. CCl2F2 (Dichlorodifluoromethane)

### Step 2: Understand Refrigerants
Refrigerants are substances used in refrigeration systems to absorb heat from the environment and provide cooling. Many modern refrigerants are classified as Chlorofluorocarbons (CFCs) or Hydrofluorocarbons (HFCs). CFCs contain chlorine, fluorine, and carbon.

### Step 3: Analyze Each Option
- **Acetone**: This is a simple organic compound (C3H6O) and does not contain chlorine or fluorine. Therefore, it is not a refrigerant.

- **CCl4 (Carbon Tetrachloride)**: This compound contains chlorine but lacks fluorine. While it has been used in the past, it is not classified as a CFC.

- **CF4 (Carbon Tetrafluoride)**: This compound contains carbon and fluorine but does not contain chlorine. Therefore, it is not a CFC.

- **CCl2F2 (Dichlorodifluoromethane)**: This compound contains both chlorine and fluorine along with carbon, making it a CFC. It is commonly used as a refrigerant.

### Step 4: Conclusion
Based on the analysis, the compound that is used as a refrigerant is **CCl2F2 (Dichlorodifluoromethane)**.

### Final Answer
**CCl2F2 (Dichlorodifluoromethane)** is the correct answer.

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