Carbon dioxide is used for extinguishing fires caused by petroleum products but not fires caused by metals like Na or Mg. Explain.

Explanation

### Step-by-Step Solution:

1. **Understanding Carbon Dioxide (CO2) as a Fire Extinguisher**:
- Carbon dioxide is a non-flammable gas that is heavier than air. It works by displacing oxygen in the environment, which is essential for combustion. When CO2 is released in a fire, it reduces the amount of oxygen available for the fire to continue burning.

2. **Fires Caused by Petroleum Products**:
- Fires caused by petroleum products (like oil and gasoline) are typically fueled by hydrocarbons. These types of fires can be effectively extinguished by CO2 because it suffocates the fire by removing oxygen from the vicinity of the flames.

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