Question

Arrange the gases present in air in the ascending order of their boiling points: argon, oxygen, nitrogen.

Answer 1

Air is a mixture of mainly three gases i.e.; oxygen (O), argon (Ar), and nitrogen (N).

• Their boiling points are given in the table.

S.No.	Name of the gas	Boiling point $(°\mathrm{C})$
1	Oxygen $\left(\mathrm{O}\right)$	$-183$
2	Argon $\left(\mathrm{Ar}\right)$	$-186$
3	Nitrogen $\left(\mathrm{N}\right)$	$-196$

Step-1: Find the gas with the lowest and the highest boiling point from the known values

• Write the lowest boiling point first and the highest boiling point at the last.
• The lowest boiling point is that of nitrogen i.e.$-196°\mathrm{C}$ (due to the negative sign, the highest value will become the lowest and vice versa) and the highest boiling point is that of oxygen i.e.; $-183°\mathrm{C}$

Step-2: Arrange the boiling points in the ascending order by putting the lesser than sign as shown below.

$-196°\mathrm{C}<-186°\mathrm{C}<-183°\mathrm{C}$

Therefore, the ascending order of boiling points of gases i.e.; argon, oxygen, and nitrogen is nitrogen $<$argon $<$oxygen.