The gas present in the highest proportion in air is

The correct answer is Nitrogen.

Key Points

• Nitrogen constitutes approximately 78% of the Earth's atmosphere, making it the most abundant gas in the air.
• It is a vital component of the atmosphere but is largely inert, meaning it does not readily react with other elements under normal conditions.
• The second most abundant gas is oxygen, which makes up about 21% of the air.
• Nitrogen is essential for life on Earth as it is a key element in amino acids, proteins, and nucleic acids like DNA and RNA.
• The nitrogen cycle ensures the continuous availability of nitrogen in the ecosystem, converting it into usable forms for plants and animals.

Additional Information

• Composition of Earth's Atmosphere:
  • The atmosphere is a mixture of gases, with nitrogen (78%) and oxygen (21%) being the most abundant.
  • Other components include argon (~0.93%), carbon dioxide (~0.04%), and trace amounts of other gases like neon, helium, and methane.
• Nitrogen Cycle:
  • Nitrogen in the atmosphere is converted into usable forms like ammonia and nitrates through processes like nitrogen fixation.
  • These compounds are absorbed by plants and enter the food chain, eventually returning to the atmosphere through decomposition and denitrification.
• Importance of Nitrogen:
  • Nitrogen is a crucial element for living organisms as it is a building block of proteins and nucleic acids.
  • It is also used in industrial applications like fertilizers, explosives, and as a refrigerant.
• Other Atmospheric Gases:
  • Oxygen is essential for respiration in most living organisms and supports combustion.
  • Carbon dioxide plays a key role in photosynthesis and contributes to the greenhouse effect, regulating Earth's temperature.
  • Trace gases like methane and ozone also play significant roles in climate and atmospheric chemistry.
• Inert Nature of Nitrogen:
  • Nitrogen's triple bond in N₂ molecules makes it highly stable and non-reactive under normal conditions.
  • This inertness is beneficial for various industrial applications, including providing a non-reactive environment for chemical processes.