Q. With reference to biogas, consider the following statements:
1.Biogas primarily consists of methane (CH₄) and carbon dioxide (CO₂).
2.Biogas may contain traces of nitrogen (N₂), hydrogen (H₂), hydrogen sulphide (H₂S), and oxygen (O₂).
3.Methane alone constitutes about 95% of biogas.
Which of the statements given above is/are correct?

[A] 1 and 2 only

[B] 1 and 3 only

[C] 2 and 3 only

[D] 1, 2 and 3

Answer: A
Notes:

Explanation:

  • Statement 1 is correct: Biogas is mainly a mixture of methane and carbon dioxide.
  • Statement 2 is correct: Traces of N₂, H₂, H₂S, and O₂ are present.
  • Statement 3 is incorrect: Biogas typically contains about 50–70% methane, not 95% – the remaining major part is CO₂. The figure 95% refers to the combined proportion of CH₄ and CO₂, not methane alone.

Source- PIB

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