Question

$NH$${}_3$ gas is liquefied more easily than $N$${}_2$. Hence:

• A. vander Waal's constants '$a$' and '$b$' of $NH$${}_3$ > that of $N_2$
• B. vander Waal's constants '$a$' and '$b$' of $N{H}_3$ < that of $N_2$
• C. $a\left(N{H}_3\right)$ > $a\left(N_2\right)$ but $b\left(N{H}_3\right)$ < $b\left(N_2\right)$
• D. $a\left(N{H}_3\right)$ < $a\left(N_2\right)$ but $b\left(N{H}_3\right)$ > $b\left(N_2\right)$

Answer 1

The correct option is C $a\left(N{H}_3\right)$ > $a\left(N_2\right)$ but $b\left(N{H}_3\right)$ < $b\left(N_2\right)$

$N{H}_3$ gas is liquefied more easily than $N_2$ Hence $a\left(N{H}_3\right)$ > $a\left(N_2\right)$ but $b\left(N{H}_3\right)$ < $b\left(N_2\right)$
The van der waals constant '$a$' represents the magnitude of the attractive forces present between gas molecules. Higher is the value of '$a$', more easily the gas can be liquefied. The van der waals constant '$b$' represents the effective size of gas molecules. Higher is the value of '$b$', larger is the size and smaller is the compressible volume and more difficult it is to liquefy the gas.