Question

Gobar gas contains mainly
a. $CH_4 + CO_2$
b. $CH_4 + O_2$
c. $CO_2 + H_2$
d. $CO_2 + SO_2$

Answer 1

Hint: Biogas, also known as gobar gas produced from organic matter in a biogas plant through a process called digestion in absence of oxygen by microorganisms, such as methanogens and sulfate-reducing bacteria.

Complete answer:
Biogas is produced from organic matter in a biogas plant through a process called digestion in absence of oxygen.
- It is commonly known as gobar gas in India.
- It mainly consists of methane and carbon dioxide and may have small amounts of hydrogen sulfide (H2S), moisture and siloxanes.
- It can be produced from agricultural, municipal and household wastes.
- It is a renewable energy source as well as a clean source of energy.
- It can be produced by microorganisms, such as methanogens and sulfate-reducing bacteria.
- It is known as an environmentally-friendly energy due to following reasons:
- It reduces demand of fossil fuel energy to meet global energy demand
- The conversion of organic waste into biogas minimizes production of methane gas, as efficient combustion replaces methane with carbon dioxide.

Hence, the correct answer is option (A).

Additional information:
Uses of Gobar Gas
- It can be used for cooking.
- It can be used as boiler fuel.
- Large scale production of biogas can be used for electricity and heat generation using a combined heat and power.

Disadvantages of Biogas
- It can cause air pollution similar to that of natural gas.
- Toxic content of hydrogen sulfide can be responsible for serious accidents as it is corrosive and inflammable.
- Leakage of unburned methane is an additional risk as it is a potent greenhouse gas.

Note: Methane is a greenhouse gas and is nearly 21 times more effective in trapping heat in the atmosphere than carbon dioxide. Therefore, biogas combustion results in a net reduction in greenhouse gas emissions.