Question

Which gas is abundant in air ?

Answer 1

Hint: Any element or gas which is present in plenty in the atmosphere is called an abundant element or gas. Abundant element or gas has so many main sources for its presence. Abundant means something which is present in large quantities. Example: Earth has abundant Water because almost 71% of the earth is covered with water and remaining almost 29% of the earth consists of the land .

Complete answer:
The most abundant gas in the atmosphere is nitrogen, with oxygen second. Argon, an inert gas, is the third most abundant gas in the atmosphere. The atmosphere is composed of a mix of several gases in differing amounts. The permanent gases whose percentages do not change from day to day are nitrogen, oxygen and argon. Nitrogen accounts for 78% of the atmosphere, oxygen 21% and argon 0.9%. Nitrogen is so enriched in the atmosphere relative to oxygen because it is very stable in the atmosphere and is not involved to a great extent in chemical reactions.
There are also trace amounts of carbon dioxide ( $C{O}_2$ ), neon ( $Ne$ ), helium ( $He$ ), methane ( $C{H}_4$ )Krypton ( $Kr$ ), hydrogen ( $H_2$ ), nitrous oxide ( $NO$ ), xenon ( $Xe$ ), ozone ( $O_3$ ), iodine ( $I_2$ ), carbon monoxide ( $CO$ ), and ammonia ( $N{H}_3$ ) in the atmosphere. As we know carbon exists as carbon dioxide gas( ). It is present in Earth's atmosphere at a low concentration and it also acts as greenhouse gas. In the solid state it is called dry ice. The current concentration of carbon dioxide is 0.04% in earth's atmosphere. The main sources of Carbon dioxide are:Ocean release and respiration , human sources come from activities like cement production,deforestation as well as the burning of fossil fuels like coal, oil and natural gas are also its main sources. Nitrogen $(N_2)$ gas is a colorless, odorless and tasteless gas. It is nonflammable and it doesn't support any combustion. It accounts for 78% of the atmosphere. The main sources of Nitrogen gas are:Atmospheric precipitation, geological sources, agricultural land, livestock and poultry operations and urban waste. Oxygen is the third most abundant element in the universe and the most abundant element by mass in the earth's crust. It exists as gas and constitutes about the volume of air. The main sources of oxygen are: Breathing of plants and animals and decomposition of dead plant and animal material.
Argon is Colorless, odourless, non-reactive, inert gas. It accounts for vol. The main source of argon gas is: Decay of potassium -40 in the earth crust. So from above, we can conclude that argon is the third most abundant gas in the Earth's atmosphere.

Note:
Always try to remember the percentage volume of top-4 abundant gases. The composition of the air in earth's atmosphere is: nitrogen — 78 percent; oxygen — 21 percent; argon — 0.93 percent; carbon dioxide — 0.04 percent; and some amounts of neon, helium, methane, krypton and hydrogen, as well as water vapor are also present.