Which of these is not a harmful gas released during the burning of fossil fuels such as petrol and diesel?

Options

A. `O_(2)`
B. `CO`
C. `CO_(2)`
D. `SO_(2)`

Answer

To solve the question "Which of these is not a harmful gas released during the burning of fossil fuels such as petrol and diesel?", we can follow these steps:

### Step-by-Step Solution:

1. **Identify the gases released during combustion**: When fossil fuels like petrol and diesel are burned, they release several gases. The primary gases include carbon dioxide (CO2), sulfur dioxide (SO2), and nitrogen oxides (NOx).

2. **Understand the nature of these gases**:
- **Carbon Dioxide (CO2)**: This is a greenhouse gas that contributes to global warming, and while it is not toxic in small amounts, it is still considered harmful in the context of climate change.
- **Sulfur Dioxide (SO2)**: This gas can cause acid rain and respiratory problems, making it harmful to both the environment and human health.
- **Nitrogen Oxides (NOx)**: These gases can lead to smog and respiratory issues, thus are also harmful.

3. **Consider the options given**: The question asks for a gas that is not harmful. The options typically include gases like CO2, SO2, and possibly oxygen (O2).

4. **Identify the non-harmful gas**: Among the gases mentioned, oxygen (O2) is essential for combustion but is not harmful in the context of burning fossil fuels. It is a natural component of the atmosphere and is vital for life.

5. **Conclusion**: Therefore, the gas that is not harmful when fossil fuels are burned is **oxygen (O2)**.

### Final Answer:
The gas that is not harmful released during the burning of fossil fuels such as petrol and diesel is **oxygen (O2)**.

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