Which is not a green house gas ?

Options

A. Chlorofuorocarbon
B. Methane
C. Carbon dioxide
D. Hydrogen

Answer

To determine which gas is not a greenhouse gas, we need to understand what greenhouse gases are and their role in the greenhouse effect.

### Step-by-Step Solution:

1. **Define Greenhouse Gases**: Greenhouse gases are gases that trap heat in the atmosphere and contribute to the greenhouse effect. This effect occurs when the sun's energy reaches the Earth, and some of that energy is reflected back into space. Greenhouse gases absorb and re-radiate this energy, warming the atmosphere.

2. **Identify Common Greenhouse Gases**: Common greenhouse gases include carbon dioxide (CO2), methane (CH4), and chlorofluorocarbons (CFCs). These gases can trap heat effectively and contribute to global warming.

3. **Analyze the Options**: The options provided are:
- Option 1: Chlorofluorocarbon (CFC)
- Option 2: Methane (CH4)
- Option 3: Carbon dioxide (CO2)
- Option 4: Hydrogen (H2)

4. **Evaluate Each Option**:
- **Chlorofluorocarbon (CFC)**: This is a greenhouse gas that contributes to ozone depletion and has a significant warming potential.
- **Methane (CH4)**: This is a potent greenhouse gas that is much more effective than CO2 at trapping heat in the atmosphere.
- **Carbon dioxide (CO2)**: This is one of the primary greenhouse gases and is a major contributor to the greenhouse effect.
- **Hydrogen (H2)**: Hydrogen is a simple diatomic molecule that does not have the capacity to trap heat in the atmosphere. It is not considered a greenhouse gas.

5. **Conclusion**: Based on the analysis, the gas that is not a greenhouse gas is **Option 4: Hydrogen (H2)**.

### Final Answer:
The gas that is not a greenhouse gas is **Hydrogen (H2)**.

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