What are the properties of `CO_2`?

Explanation

### Step-by-Step Solution for the Properties of CO₂ (Carbon Dioxide)

1. **State the Chemical Formula**:
- Carbon dioxide is represented by the chemical formula CO₂.

2. **Physical State**:
- Carbon dioxide exists in different physical states:
- **Solid State**: In solid form, it is commonly known as dry ice.
- **Liquid State**: CO₂ can also exist in a liquid state under specific conditions of temperature and pressure.

3. **Uses in Refrigeration**:
- Both solid (dry ice) and liquid CO₂ are utilized for refrigeration and cooling purposes due to their ability to absorb heat effectively.

4. **Inert Gas Properties**:
- CO₂ is used as an inert gas in various chemical processes. Its inert nature makes it suitable for preventing unwanted reactions during storage and handling of reactive materials.

5. **Fire Extinguishing Agent**:
- Carbon dioxide is widely used in fire extinguishers. It works by displacing oxygen in the vicinity of the fire, thus helping to extinguish flames.

6. **Applications in Metal Industry**:
- In the metal industry, CO₂ is utilized in the manufacturing of casting molds. It enhances the hardness of these molds, making them more durable and effective for casting processes.

### Summary of Properties:
- **Chemical Formula**: CO₂
- **Physical States**: Solid (dry ice), Liquid
- **Refrigeration and Cooling**: Used in both solid and liquid forms.
- **Inert Gas**: Used in chemical processes and storage.
- **Fire Extinguisher**: Effective in extinguishing fires by displacing oxygen.
- **Metal Industry**: Enhances hardness of casting molds.

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