Question

The value of van der Waals constant '$a$' for gases $O_2,N_2,N{H}_3$ and $C{H}_4$ are 1.360, 1.390, 4.170 and 2.253 litre${}^2$ atm mol${}^{-2}$ respectively. The gas which can most easily be liquefied, is:

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

Answer 1

The correct option is C $N{H}_3$

Van der Waals constant for attraction ($a$) and volume ($b$) are characteristic for a given gas.
Some salient features of $a$ and $b$ are:
The gas having higher value of '$a$' can be liquefied easily and therefore, hydrogen and helium are not liquefied easily.
So here, $N{H}_3$ will be liquefied easily.