Q. Which of the following two are the major constituent of Bio-gas ?
1. Methane
2. Butane
3. Carbon dioxide
4. Carbon monoxide
Select the correct answer from the code given below :
a) 1 and 3
b) 3 and 4
c) 2 and 3
d) 1 and 2
Correct Answer: a) 1 and 3
Question from UPPSC Prelims 2025
Explanation:
Biogas is produced by anaerobic digestion of organic matter. Its major constituents are methane (about 50–70%) and carbon dioxide (about 30–45%), with traces of H2S, H2, N2, and water vapor.
– Option 1 (1 and 3): Correct — Methane and carbon dioxide are the two major components of biogas.
– Option 2 (3 and 4): Incorrect — Carbon monoxide is not a major component of biogas; CO is typical of producer gas/syngas from gasification, not anaerobic digestion.
– Option 3 (2 and 3): Incorrect — Butane is not produced in biogas; it is a component of LPG.
– Option 4 (1 and 2): Incorrect — Includes butane, which is not a constituent of biogas.
