Biogas produced by anaerobic fermentation of water biomass consists of

Options

A. methane
B. traces of `H_(2), H_(2)S and N_(2)`
C. `CO_(2)`
D. all of these

Answer

To answer the question regarding the composition of biogas produced by anaerobic fermentation of water biomass, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Biogas**:
- Biogas is a mixture of gases produced by the breakdown of organic matter in the absence of oxygen (anaerobic fermentation).

2. **Main Components of Biogas**:
- The primary component of biogas is **methane (CH4)**, which is a significant renewable energy source.
- Another major component is **carbon dioxide (CO2)**, which is produced alongside methane during the fermentation process.

3. **Trace Gases**:
- In addition to methane and carbon dioxide, biogas may contain trace amounts of other gases:
- **Hydrogen (H2)**: Present in small quantities.
- **Hydrogen Sulfide (H2S)**: A toxic gas that can also be found in trace amounts.
- **Nitrogen (N2)**: May also be present in small amounts.

4. **Conclusion**:
- Therefore, biogas produced by anaerobic fermentation of water biomass consists of a mixture of methane, carbon dioxide, traces of hydrogen, hydrogen sulfide, and nitrogen.

5. **Final Answer**:
- The correct option is **all of these**.