Question

The value of van derWaals' constant a for the gases $O_2, N_2$, $NH_3$ and $CH_4$ are 1.360, 1.390,4.170 and $2.253L^2$ atm $mol^{-2}$ respectively. The gas which can most easily be liquefied is

• A. $O_2$
• B. $N_2$
• C. $NH_3$
• D. $CH_4$

Answer 1

Answer: (C)

$NH_3$

Answer 2

The ease of liquefication of a gas depends on their intermolecular force of attraction which in turn is measured in terms of van der Waals' constant a. Hence, higher the value of a, greater the intermolecular force of attraction, easier the liquefication. In the present case, $NH_3$ has highest a, can most easily be liquefied.