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Components of Air - Oxygen, Nitrogen, Carbon Dioxide, Water with FAQs

Components of Air - Oxygen, Nitrogen, Carbon Dioxide, Water with FAQs

Edited By Team Careers360 | Updated on Jul 02, 2025 05:03 PM IST

After reading this article, the reader should be able to understand - Introduction of air, Name the major component of air, Nitrogen present in the atmosphere, air percentage, Name the main components of air, what are the components of air, Amount of nitrogen in the atmosphere, Composition of gases in the air, what does air contain.

Air-

  • Air that we breathe in is available anytime and anywhere around us. Air cannot be seen as the other necessities of life such as water, sun, and food.
  • Dip an empty bottle in a large container of water. You will observe bubbles evolving out of it. It means you are replacing the air present in the bottle with water without seeing it. However, the air is an indispensable part of our lives. Let us see what makes air a crucial part of life and what are the constituents of air.
  • Air is a mixture of gases that is a part of the atmosphere. The major components of the atmosphere are substances such as air, water vapors, and dust particles.
  • The major component of air is composed of nitrogen and oxygen alone.
  • Until the 15th century, the air was considered to be an element. Not long after, Lavoisier became the first scientist to recognize that the ratio of nitrogen to oxygen in the air is 4:1.
  • A Large Percentage of air in the atmosphere has nitrogen and oxygen as the major components. The atmosphere protects us from hazardous radiations of the space and extends up to a height of 20 km and above. There is a Huge Difference between air and oxygen that we will see in a while.

Also read -

Constituents of air (percentage of gases in air)

Air contains a mixture of gases. A considerable segment of the air is constituted by oxygen and Nitrogen. The major component of air is composed of active and inactive components.

However, this mixture of many gases has the highest percentage of nitrogen in atmosphere which is an inactive component. The percentage of nitrogen in air is 78% and O2 percentage in the air is 21%.

Nitrogen is the inactive part of the atmosphere because it cannot be directly used by us and oxygen in the air is the active part of the atmosphere because it supports life.

Air consists of many harmful particles like smoke and dust particles. Smoke consists of nanosized carbon particles that remain unburnt during the burning of a fuel.

Constituents of air diagramConstituents of Air Diagram

Above is a pie chart showing the composition of air and present gases in the atmosphere and their percentages.

The various constituents of air and their uses are given below-

Oxygen-

  • Carl Scheele was the first scientist to witness combustion supporting the nature of oxygen in the air. Names like “vital air” and “fire air” were given to oxygen.
  • Oxygen was prepared in many ways like by decomposition of mercuric oxide and by focusing sun rays through the convex lens on mercuric oxide.
  • Later Antoine Lavoisier proved oxygen to be an element. The name ‘Oxygen’ was given by Lavoisier after he found oxygen helpful in the production of acid.
  • Free state- Atmospheric air consists of oxygen in its elemental state as 21% by volume and 23% by mass.
  • Combined state- the percentage of oxygen in water is a tiny amount as compared to the percentage present in air i.e.,1%. This oxygen exists in water in a combined state and is the source of survival for aquatic life.

Chemical properties of oxygen-

  • The component of air that supports combustion is oxygen. The volume of oxygen in air supports combustion however it doesn't burn on its own. Hence, it’s a non-combustible gas.
  • Oxygen supports rusting in which iron gets converted to rust (a hydrated form of iron).
  • It is neutral (neither acidic nor basic,)

Uses of Oxygen-

  • Respiration- Living beings inhale oxygen and ultimately produce energy.
  • Used in carbogen (a mixture of 95% oxygen and 5% carbon dioxide) given to patients with breathing problems.
  • Oxygen is essential for the ignition of fuels.
  • Cartridge- A mixture of liquid oxygen, liquid petroleum, and coal is used for blasting mountains.

Carbon dioxide-

  • Carbon dioxide is the fifth abundant gas in the atmosphere. It occurs in 0.003% of the total volume of air.
  • It is an odorless gas that is highly soluble.
  • It is heavier than air and is acidic.
  • Carbon dioxide occurs if free as well as in a combined state. In combined forms, it exists as carbonates in limestone, dolomite, etc. It is present in its free state in water bodies like lakes, oceans, etc.
  • Carbon dioxide was first called Carbonium by van Helmont and later it was called acid carbonium by Lavoisier.
  • Joseph Black synthesized the gas by heating magnesium carbonate.

Chemical properties of Carbon dioxide-

  • It has no combustibility properties as it is not a combustible gas and cannot support combustion.
  • When CO2 reacts with water it becomes acidic. The compound formed is known as carbonic acid.
  • Carbon dioxide is produced when coal and natural gas are formed.
  • Carbon dioxide reacts with metals and non-metals to form metal carbonates and metal oxides respectively.

Uses of Carbon dioxide-

  • It is an important compound for the formation of sodium hydrogen carbonate, washing soda, etc.
  • The tangy taste of soft drinks is imparted due to dissolved carbon dioxide in liquids.
  • It is used for the preservation of food items.
  • CO2 present in the atmosphere is taken up by the plants through photosynthesis to produce oxygen.
  • Dry ice is used in refrigerators to store fruits and vegetables.

Also Read:

Nitrogen-

The percentage of nitrogen in air is 78% by volume Main component of air is nitrogen gas.

  • Like carbon dioxide and oxygen, nitrogen also exists in combined and free states. Examples- KNO3,NaNO3, etc.
  • Nitrogen in the air is also an inactive component of the atmosphere since it weakens the activity of oxygen and slows down the rapid burning.

Chemical properties of Nitrogen-

  • Nitrogen fixation- Elemental state of nitrogen in the air is present in the atmosphere in a free state but cannot be directly used therefore, it is first fixed by leguminous plants by converting nitrogen into essential compounds of nitrogen. This process is called nitrogen fixation which is very essential to make use of the nitrogen present in the atmosphere.
  • Leguminous plants have symbiotic bacteria in their root nodules which assimilate nitrogen present in the atmosphere and convert it into essential nitrogen compounds.

Uses of nitrogen-

  • Nitrogen is used for the conservation of food items since it is chemically inert.
  • Nitrogen is essential for the synthesis of proteins.
  • Nitrogen (i.e., a major component of air) slows down the activity of oxygen.

Hydrogen-

  • Hydrogen is mostly found in the combined state in various carbon compounds such as vitamins, nucleic acids, enzymes, etc.
  • Non-living matter such as wood, paper, and rubber contains hydrogen.
  • Henry Cavendish was the first person to establish the elemental nature of hydrogen.
  • The first method to produce hydrogen was from the action of sulfuric acid on metals.
  • The name hydrogen means water producing. Hydro means water and gen means to produce.
  • Hydrogen is the lightest element that is present in trace amounts in the atmosphere.

Chemical properties of hydrogen-

  • Hydrogen storage is a major issue since it reacts with oxygen and burns in the air.
  • Hydrogen reacts with non-metals to form metal hydrides.
  • Hydrogen reacts with nitrogen in the ratio of 3:1 to form ammonia.
  • Hydrogen adds to many unsaturated molecules to form saturated molecules. This is known as hydrogenation.

Uses of hydrogen-

  • Hydrogen is essential in Haber’s process for the formation of ammonia.
  • Many other important compounds such as hydrogen chloride and methyl alcohol are synthesized with the help of hydrogen.
  • Hydrogen is used to extract some metals from their oxides.
  • Hydrogen can react with compounds in the form of nascent hydrogen [H]. This nascent hydrogen is called newly born hydrogen. This is important for the compounds which do not react with hydrogen originally.

Also check-

NCERT Chemistry Notes:

Frequently Asked Questions (FAQs)

1. Which is the least component present in the air?

The least percentage of air is 1% which is composed of particles and gases such as inert gases, carbon dioxide, hydrogen, smoke, and dust particles. 

2. What percentage of the atmosphere is nitrogen?

78% of the air by volume percentage is composed of nitrogen gas.

3. Why is nitrogen 78 percent of the atmosphere?

Nitrogen content in the air is the highest. Although this nitrogen present cannot be directly used. This nitrogen is first converted by the leguminous plants in their root nodules to synthesize nitrogen compounds. This process is called nitrogen fixation. 

4. What is the major component of air?

A major component of air is Nitrogen gas (78%). It is an inactive component of the air and slows down the activity of oxygen.

5. Write a composition of air.

Air is mainly composed of nitrogen (78%), oxygen (21%), trace gases (1%) such as inert gases, water vapors, smoke, and dust particles.

6. What are the major constituents of air?

Nitrogen and oxygen together make the major constituent of air (78%+21%) =99% 

7. What are the main components of air?
The main components of air are nitrogen (78%), oxygen (21%), argon (0.93%), and carbon dioxide (0.04%). Other trace gases and water vapor are also present in varying amounts.
8. Why is nitrogen the most abundant gas in Earth's atmosphere?
Nitrogen is the most abundant gas in Earth's atmosphere because it is chemically unreactive under normal conditions. This stability allows nitrogen to accumulate over time without being easily removed by natural processes.
9. How does the composition of air change with altitude?
As altitude increases, the overall air density decreases. The proportion of lighter gases like hydrogen and helium increases, while heavier gases like oxygen and carbon dioxide decrease. Water vapor content also generally decreases with altitude.
10. What role does oxygen play in the atmosphere?
Oxygen is crucial for life on Earth. It supports respiration in many organisms, enables combustion processes, and plays a vital role in the ozone layer, which protects the Earth from harmful ultraviolet radiation.
11. How do plants and animals affect the balance of oxygen and carbon dioxide in the air?
Plants consume carbon dioxide and release oxygen through photosynthesis, while animals consume oxygen and release carbon dioxide through respiration. This creates a natural balance in the atmosphere, known as the carbon-oxygen cycle.
12. What is the greenhouse effect, and how does carbon dioxide contribute to it?
The greenhouse effect is the warming of Earth's surface due to certain gases trapping heat in the atmosphere. Carbon dioxide is a major greenhouse gas that absorbs and re-emits infrared radiation, contributing significantly to global warming.
13. How does water vapor in the air affect weather patterns?
Water vapor plays a crucial role in weather patterns by forming clouds, precipitation, and influencing atmospheric pressure. It also acts as a greenhouse gas, affecting Earth's energy balance and climate.
14. Why is argon present in the atmosphere, and what are its properties?
Argon is present in the atmosphere due to the radioactive decay of potassium in the Earth's crust. It's an inert noble gas, meaning it doesn't react with other elements, allowing it to accumulate in the atmosphere over time.
15. How do human activities affect the composition of air?
Human activities like burning fossil fuels, deforestation, and industrial processes release pollutants and greenhouse gases into the air. This can lead to increased levels of carbon dioxide, methane, and other pollutants, altering the atmosphere's composition.
16. What is the ozone layer, and why is it important?
The ozone layer is a region in the Earth's stratosphere containing a high concentration of ozone (O₃). It's crucial because it absorbs most of the Sun's harmful ultraviolet radiation, protecting life on Earth from its damaging effects.
17. How does air pollution affect the composition of the atmosphere?
Air pollution introduces harmful substances like particulate matter, sulfur dioxide, and nitrogen oxides into the atmosphere. These pollutants can react with other components of air, altering its composition and potentially leading to acid rain, smog, and other environmental issues.
18. What is the difference between tropospheric and stratospheric ozone?
Tropospheric ozone (ground-level ozone) is a pollutant formed by chemical reactions between nitrogen oxides and volatile organic compounds. Stratospheric ozone, on the other hand, forms naturally in the upper atmosphere and protects Earth from harmful UV radiation.
19. How does the carbon cycle influence atmospheric carbon dioxide levels?
The carbon cycle involves the exchange of carbon between the atmosphere, oceans, land, and living organisms. Natural processes like photosynthesis and respiration, as well as human activities like burning fossil fuels, affect atmospheric CO₂ levels through this cycle.
20. What is the role of methane in the atmosphere?
Methane is a potent greenhouse gas that contributes to global warming. It's produced by natural sources like wetlands and human activities such as agriculture and fossil fuel extraction. Although less abundant than CO₂, it has a stronger warming effect per molecule.
21. How do volcanic eruptions affect air composition?
Volcanic eruptions release gases like sulfur dioxide, carbon dioxide, and water vapor into the atmosphere. These emissions can temporarily alter air composition, affect climate, and in some cases, lead to the formation of acid rain.
22. What is the significance of the nitrogen cycle in maintaining atmospheric composition?
The nitrogen cycle is crucial for maintaining the balance of nitrogen in the atmosphere. It involves processes like nitrogen fixation by bacteria, nitrification, denitrification, and the decomposition of organic matter, which help regulate atmospheric nitrogen levels.
23. How does air pressure change with altitude, and why?
Air pressure decreases with increasing altitude because there's less air above to exert downward force. This relationship is exponential, with pressure decreasing more rapidly at lower altitudes and more gradually at higher altitudes.
24. What is the role of aerosols in the atmosphere?
Aerosols are tiny particles suspended in the air, including dust, sea salt, and pollutants. They play a complex role in climate by scattering or absorbing sunlight and influencing cloud formation, potentially cooling or warming the Earth's surface.
25. How do seasonal changes affect air composition?
Seasonal changes can affect air composition through variations in temperature, humidity, and biological activity. For example, CO₂ levels fluctuate annually due to increased plant growth in spring and summer, which removes more CO₂ from the atmosphere.
26. What is the importance of trace gases in the atmosphere?
Trace gases, despite their low concentrations, can have significant impacts on atmospheric chemistry and climate. For example, CFCs, even in small amounts, can cause substantial damage to the ozone layer.
27. How does the water cycle interact with atmospheric composition?
The water cycle, or hydrologic cycle, involves the continuous movement of water within the Earth and atmosphere. It affects atmospheric composition by influencing humidity levels, cloud formation, and precipitation, which in turn impact the distribution of water vapor and other gases in the air.
28. What is the difference between weather and climate in terms of atmospheric composition?
Weather refers to short-term atmospheric conditions, while climate describes long-term patterns. Atmospheric composition affects both: short-term changes can influence daily weather, while long-term changes in greenhouse gas concentrations can alter climate patterns over time.
29. How do oceans influence atmospheric carbon dioxide levels?
Oceans act as a major carbon sink, absorbing about 25% of human-produced CO₂. This process helps regulate atmospheric CO₂ levels but also leads to ocean acidification as the absorbed CO₂ reacts with seawater to form carbonic acid.
30. What is the urban heat island effect, and how does it relate to air composition?
The urban heat island effect occurs when cities are significantly warmer than surrounding rural areas due to human activities and urban infrastructure. This phenomenon can alter local air composition by increasing ground-level ozone formation and affecting air circulation patterns.
31. How do forests impact atmospheric oxygen and carbon dioxide levels?
Forests act as important carbon sinks, absorbing CO₂ through photosynthesis and storing it in biomass and soil. They also release oxygen as a byproduct of photosynthesis, playing a crucial role in maintaining the balance of these gases in the atmosphere.
32. What is the role of hydrogen in the upper atmosphere?
Hydrogen, the lightest element, is present in small quantities in the upper atmosphere. It plays a role in the formation of water vapor and can escape into space due to its low molecular weight, contributing to the gradual loss of Earth's atmosphere over geological time scales.
33. How do air pollutants like sulfur dioxide and nitrogen oxides affect cloud formation?
Sulfur dioxide and nitrogen oxides can act as cloud condensation nuclei, promoting the formation of water droplets. This can lead to increased cloud cover and potentially affect precipitation patterns and Earth's energy balance.
34. What is the significance of the stratospheric temperature inversion?
The stratospheric temperature inversion, where temperature increases with altitude, is crucial for atmospheric stability. It prevents vertical mixing between the troposphere and stratosphere, helping to maintain the ozone layer and influencing weather patterns.
35. How do changes in atmospheric composition affect the Earth's radiation balance?
Changes in atmospheric composition, particularly in greenhouse gas concentrations, alter the Earth's radiation balance. Increased levels of gases like CO₂ and methane enhance the greenhouse effect, trapping more heat and potentially leading to global warming.
36. What is the role of noble gases other than argon in the atmosphere?
Noble gases like neon, helium, krypton, and xenon are present in trace amounts in the atmosphere. While they don't participate in chemical reactions, they play roles in various natural processes and have applications in scientific research and technology.
37. How does air density vary with temperature and humidity?
Air density decreases as temperature increases because warm air expands. Humidity also affects air density
38. What is the importance of the mesosphere in the Earth's atmosphere?
The mesosphere is important for protecting the Earth from meteors, which typically burn up in this layer due to friction. It also plays a role in the formation of noctilucent clouds and is a region where atmospheric tides and gravity waves are studied.
39. How do chlorofluorocarbons (CFCs) affect the ozone layer?
CFCs, when released into the atmosphere, rise to the stratosphere where they are broken down by UV radiation. This process releases chlorine atoms that catalyze the destruction of ozone molecules, leading to the depletion of the ozone layer.
40. What is the role of cosmic rays in atmospheric chemistry?
Cosmic rays, high-energy particles from space, interact with atmospheric gases, producing secondary particles and ionizing molecules. This process can influence cloud formation and contribute to the production of certain isotopes used in climate research.
41. How does atmospheric composition affect the color of the sky?
The blue color of the sky is due to Rayleigh scattering of sunlight by air molecules. The composition of the atmosphere, particularly the presence of particles and water vapor, can affect this scattering, leading to variations in sky color, especially during sunrise and sunset.
42. What is the significance of the atmospheric boundary layer?
The atmospheric boundary layer is the lowest part of the troposphere that is directly influenced by the Earth's surface. It plays a crucial role in the exchange of heat, moisture, and pollutants between the surface and the atmosphere, affecting local weather and air quality.
43. How do atmospheric ions contribute to air chemistry?
Atmospheric ions, created by cosmic rays and radioactive decay, play a role in various atmospheric processes. They can influence cloud formation, participate in chemical reactions, and affect the electrical properties of the atmosphere.
44. What is the importance of atmospheric circulation in distributing air components?
Atmospheric circulation patterns, such as the Hadley, Ferrel, and polar cells, distribute heat, moisture, and various atmospheric components globally. This circulation is crucial for maintaining temperature gradients and influencing weather patterns across the planet.
45. How does the presence of dust particles in the atmosphere affect climate?
Atmospheric dust particles can have both cooling and warming effects on climate. They can reflect sunlight back to space, causing cooling, or absorb solar radiation, leading to warming. Dust also plays a role in cloud formation and can affect precipitation patterns.
46. What is the role of atmospheric pressure in weather systems?
Atmospheric pressure differences drive wind patterns and the movement of weather systems. High-pressure areas typically bring fair weather, while low-pressure areas are associated with clouds, precipitation, and potentially stormy conditions.
47. How do changes in solar activity affect the Earth's atmosphere?
Solar activity, such as solar flares and coronal mass ejections, can affect the upper atmosphere by altering its composition and temperature. This can impact satellite operations, radio communications, and potentially influence climate patterns on Earth.
48. What is the significance of the thermosphere in the Earth's atmosphere?
The thermosphere is important for absorbing extreme ultraviolet and X-ray radiation from the Sun. It's also the layer where auroras occur and where many satellites orbit, making it crucial for space weather and satellite communications.
49. How does air pollution affect cloud formation and precipitation?
Air pollutants can act as cloud condensation nuclei, potentially increasing cloud cover. However, excessive pollution can also suppress rainfall by creating too many small cloud droplets that don't easily coalesce into raindrops, affecting precipitation patterns.
50. What is the role of atmospheric electricity in weather phenomena?
Atmospheric electricity, including phenomena like lightning, plays a role in the nitrogen cycle by fixing atmospheric nitrogen into a form usable by plants. It also influences the formation of certain air pollutants and can affect radio wave propagation.
51. How do changes in atmospheric composition affect the Earth's albedo?
Changes in atmospheric composition can alter the Earth's albedo (reflectivity) by affecting cloud cover, aerosol concentrations, and surface properties. This, in turn, influences the amount of solar radiation reflected back to space, impacting the Earth's energy balance and climate.
52. What is the importance of the exosphere, the outermost layer of Earth's atmosphere?
The exosphere is the transition zone between Earth's atmosphere and interplanetary space. It plays a role in the escape of light gases like hydrogen and helium from Earth's atmosphere and is important for satellite operations and studies of the near-Earth space environment.
53. How do atmospheric tides affect the distribution of gases in the upper atmosphere?
Atmospheric tides, caused by solar heating and gravitational forces, create regular oscillations in atmospheric pressure, temperature, and wind. These tides can influence the distribution of gases in the upper atmosphere, affecting phenomena like airglow and ionospheric dynamics.
54. What is the role of atmospheric chemistry in the formation of acid rain?
Atmospheric chemistry plays a crucial role in acid rain formation. Sulfur dioxide and nitrogen oxides, primarily from human activities, react with water, oxygen, and other chemicals in the atmosphere to form sulfuric and nitric acids, which fall as acid rain, impacting ecosystems and infrastructure.
55. How does the presence of water vapor in the atmosphere affect the transmission of electromagnetic radiation?
Water vapor in the atmosphere absorbs and emits infrared radiation, playing a significant role in the Earth's greenhouse effect. It also affects the transmission of radio waves and other forms of electromagnetic radiation, influencing communication systems and atmospheric remote sensing techniques.
56. What is the significance of atmospheric optical phenomena like rainbows and halos?
Atmospheric optical phenomena such as rainbows, halos, and sundogs are caused by the interaction of light with water droplets, ice crystals, and other atmospheric particles. These phenomena provide information about atmospheric conditions and have historically been used for weather prediction.

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