The main constituent of biogas is ?

Biogas is a renewable energy source produced through the anaerobic decomposition (breakdown in the absence of oxygen) of organic materials such as animal dung, crop waste, and kitchen leftovers. The primary component of biogas is methane (CH₄), which usually makes up about 50–70% of its total composition. The rest includes carbon dioxide (CO₂), small amounts of hydrogen (H₂), nitrogen (N₂), and hydrogen sulfide (H₂S).

Methane is the most important part of biogas because it is the main combustible gas, meaning it can burn easily and release energy. When methane burns in the presence of oxygen, it forms carbon dioxide and water, releasing heat energy that can be used for cooking, lighting, or generating electricity.

The process of biogas production happens in a closed tank called a biogas digester. Inside the digester, microorganisms (bacteria) act on the organic matter under oxygen-free conditions. These microbes convert the complex organic compounds into simpler gases, with methane being the major product.

Biogas is considered environment-friendly because it uses waste materials and helps reduce environmental pollution. Moreover, it provides a sustainable source of energy for rural areas and reduces dependence on fossil fuels. The leftover slurry from the digester is rich in nutrients and can be used as organic fertilizer for crops.

Let’s review the options:

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  A) Methane – ✅ Correct. Main component of biogas, provides fuel value.

  
  


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  B) Hydrogen – Present in traces only.

  
  


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  C) Oxygen – Not present, as biogas forms without oxygen.

  
  


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  D) Carbon dioxide – Present but not the main component.

  
  

Thus, methane (CH₄) is the chief constituent of biogas and the key element responsible for its energy content.

✅ Correct Answer: A) Methane