Question

The volume percentage of argon in air is nearly:
A. \[\;6\% \]
B. \[10\% \]
C. \[1\% \]
D. \[75\% \]

Answer 1

Hint: Argon is the third most abundant element in the atmosphere.It is a noble gas having the symbol Ar and atomic number 18. We can naturally obtain argon by an isotope of potassium, K-40. But industrially, it is produced by fractional distillation of liquid air.

Complete step by step answer:
-Air is made up of \[78.09\% \] nitrogen, 20.955 oxygen, \[0.93\% \] argon, \[0.04\% \] carbon dioxide, and other gases in trace amounts. So, we can say that 9.3 litres of argon is present in 1 cubic metre of air or approximately 10 litres, we can say.
-It has many applications but in an environment where the substances which are generally unreactive become reactive. For example, graphite furnaces have argon which is used to prevent the combustion of graphite itself. We can also use it as a fluorescent lamp.
-To prevent the oxidation of filaments at high temperatures, we fill them with argon because it is a colourless, tasteless and odourless gas. Sometimes it becomes very difficult to detect its presence around us. It is also used as a blue laser so as to cure eye defects and to destroy tumours as well in the field of medicine. We can also produce a bluish-green laser from it.
From all this information, we confirm that the volume percentage of argon in air is 0.93% or nearly \[1\% \] .

Hence, the correct option is (C).

Note:
As per cosmic abundance, it is said that argon is the 12th most abundant element constituting \[1.288\% \] of the atmosphere by weight and \[0.934\% \] by volume. It has three isotopes, two(argon-36 and argon-38) are stable but make up only trace amounts of abundance in the atmosphere whereas the third stable isotope, argon-40 makes up \[99.60\% \] of argon on earth.