MCQ Detailed View

Marsh gas is the common name for methane, a simple hydrocarbon belonging to the alkane series. Its chemical formula is CH₄, meaning it consists of one carbon atom bonded to four hydrogen atoms. Methane is the simplest and lightest alkane and is colorless, odorless, and highly flammable under normal conditions.

The gas is called marsh gas because it is often produced naturally in marshy or swampy areas. It is formed during the anaerobic decomposition of organic matter by certain types of microorganisms, particularly methanogenic bacteria. These bacteria break down dead plant and animal materials in environments lacking oxygen, releasing methane as a byproduct.

Methane is a major component of natural gas, making up about 70–90% of its composition. It is widely used as a fuel for heating, cooking, and electricity generation due to its high energy content and clean combustion, producing mainly carbon dioxide and water.

The other options represent different hydrocarbons:

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  Ethane (C₂H₆): A two-carbon alkane, heavier than methane, used in petrochemical industries.

  
  


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  Propane (C₃H₈): A three-carbon alkane, stored as liquefied petroleum gas (LPG).

  
  


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  Butane (C₄H₁₀): A four-carbon alkane, also used in LPG and as a fuel for lighters.

  
  

While these are also alkanes, they are not referred to as marsh gas. Only methane naturally arises in marshy wetlands through biological activity.

Methane plays a significant role in the carbon cycle and is also a potent greenhouse gas, contributing to global warming when released into the atmosphere. In chemistry, it is a fundamental compound studied to understand the structure, bonding, and reactions of hydrocarbons.