Question

The value of van der Waals constant $a$ for the gases $O_2,N_2,N{H}_3,andC{H}_4$ are 1.360, 1.390, 4.170, and $2.253L^{2}atmmo{l}^{-2}$, respectively.

Which gas can most easily be liquefied?

• A. $O_2$
• B. $N_2$
• C. $N{H}_3$
• D. $C{H}_4$

Answer 1

Answer: (C)

$N{H}_3$

$[P+\frac{a{n}^2}{V^2}](V-nb)=nRT$

The van der Waals constant $a$ is used in pressure correction, and its value depends upon the intermolecular forces between the gas molecules. The larger the value of $a$ for a gas, the more easily that gas can be liquefied.
So according to value of a, $N{H}_3$ liquifies easily.