Which gas is formed by the decomposition of biomass?

Options

A. `CH_4`
B. `NO_2`
C. `SO_2`
D. `O_2`

Answer

**Step-by-Step Solution:**

1. **Understanding Biomass**: Biomass refers to organic material derived from plants and animals. It primarily consists of cellulose, hemicellulose, ashes, and organic matter.

2. **Decomposition of Biomass**: The decomposition of biomass is carried out by microorganisms, which break down the organic materials.

3. **Products of Decomposition**: When biomass decomposes, it produces various by-products, one of which is gas.

4. **Identifying the Gas**: The main gas produced during the anaerobic decomposition of biomass is biogas.

5. **Composition of Biogas**: The chief component of biogas is methane (CH4). This is the gas that is commonly associated with the decomposition of organic matter in the absence of oxygen.

6. **Eliminating Other Options**: The other gases listed in the options (NO2, SO2, O2) are not produced during the anaerobic decomposition of biomass. Nitrogen dioxide (NO2) and sulfur dioxide (SO2) are pollutants, and oxygen (O2) is not produced in anaerobic conditions.

7. **Conclusion**: Therefore, the gas formed by the decomposition of biomass is methane (CH4).

**Final Answer**: CH4 (methane) is the gas formed by the decomposition of biomass.

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