Chemistry - Real Gas Question with Solution | TestHub

Gases with a higher critical temperature ($T_c$) are easier to liquefy because the intermolecular forces of attraction are stronger, allowing them to be liquefied at higher temperatures with sufficient pressure. The gas with the lowest critical temperature is the most difficult to liquefy and will liquefy last.

Order the gases by critical temperature

The critical temperatures provided are:

O₂: $154.3$ K

N₂: $126$ K

H₂: $33.2$ K

He: $5.3$ K

Ordering from highest $T_c$ to lowest $T_c$ gives the order of liquefaction (first to last): O₂, N₂, H₂, He.

Answer:

The correct option is (D) O₂, N₂, H₂, He.