Question

Which among the following is the main constituent of biogas?
A. Methane
B. Propane
C. Butane
D. Ethane

Answer 1

Hint: Biogas is a pure energy source. Biogas helps in recycling the waste produced in the ecology thus reducing the quantity of waste. 65% include methane gas.

Complete step by step solution:
Energy sources are of two types-renewable and non-renewable energy sources. Renewable energy is the energy produced from natural resources. E.g. Solar, wind, hydro, geothermal, biogas. Non-renewable energy is the energy which cannot be obtained from natural resources. E.g. Oil, natural gas, coal etc.
Biogas is an example for renewable energy. The organic substances are degraded and broken down into gases in the absence of oxygen. This is termed as biogas. Organic waste obtained locally is the main source of raw materials. The process is done by anaerobic bacteria. It is an organism which grows in the absence of oxygen. The anaerobic bacteria break down the materials in the absence of oxygen or by fermentation. Fermentation defines that the materials are degraded chemically by any micro-organisms which gives heat. The biodegradable waste includes sewage waste, organic manure, green waste, plant waste and even kitchen waste. The decomposition process releases several gases which mainly include methane and carbon dioxide. One disadvantage of this process is that it produces methane gas which is harmful.

Hence, option A is correct.

Additional information:
The process involves four stages. Initial stage is hydrolysis. Carbohydrates like compounds are converted. Second stage involves converting amino acids, sugar to hydrogen, ammonia, organic acids and carbon dioxide. The third stage is the organic acids converted to acetic acids, hydrogen, ammonia and carbon dioxide. Last stage includes final constituents converting to methane and carbon dioxide.

Note: Biogas is also known as clean and efficient fuel since only biodegradable materials are used in this process. Flammable gas (deep blue flame) is also produced which is further used as an energy source. Nowadays biogas is found in most of the houses in villages and towns. It is therefore denoted that it is eco-friendly.