Question

The gas, which is present the most in air, is ……..
A. oxygen
B. nitrogen
C. carbon dioxide
D. water vapor

Answer 1

Hint:In this question, we need to comment on the gaseous substances present in the atmosphere. For this we will use the concept that the earth’s atmosphere is the layer of gases.

Complete step by step answer:
 The chart below shows the gases present in the atmosphere percentage-wise.

Gases	Percentage of gases
Nitrogen $\left(N_2\right)$	$78\mathrm{\%}$
Oxygen $\left(O_2\right)$	$21\mathrm{\%}$
Organ $\left(Ar\right)$	$0.93\mathrm{\%}$
Carbon dioxide $\left(C{O}_2\right)$	$$0.04\mathrm{\%}$$

From the table shared above, we can see that the major gases present in the atmosphere are nitrogen $\left(N_2,78\mathrm{\%}\right),$ Oxygen $\left(O_2,21\mathrm{\%}\right),$ Organ $\left(Ar,0.93\mathrm{\%}\right)$ , etc. Among all the gases present in the atmosphere, nitrogen constitutes the highest amount. The percentage of nitrogen present in the atmosphere is $78\mathrm{\%}.$ After the nitrogen, the second highest percentage concentration in air is for oxygen which constitutes almost 21% of the total gases.
Only nitrogen and oxygen constitutes about 99% of the total concentration of the gases in the atmosphere and the rest 1% is occupied by other gases.
Hence option (B) is the correct answer.

Note:The gases in the atmosphere surround the earth like a blanket. This keeps the temperature range at a limit that can support life. The gas named `Radon’ is not found in the atmosphere. The earth atmosphere is mostly made of Nitrogen $\left(78\mathrm{\%}\right)$ and Oxygen $\left(21\mathrm{\%}\right).$ Some other gases like Neon $$\left(Ne\right),$$ Helium $$\left(He\right),$$ Methane$\left(C{H}_4\right)$, Crypton $$\left(Kr\right)$$ , and Hydrogen $\left(H_2\right)$, and water vapor are also present with less percentage $\left(\mathrm{\%}\right)$ amount with respect to the gases shown in the chart/ column.