In the $Vander$ $Waals$ equation,the constant $'b'$ is a measure of $......$.

The compressibility factor $(Z)$ of a gas is less than unity at $STP$,then:

Assertion : Compressibility factor for hydrogen varies with pressure with positive slope at all pressures.
Reason : Even at low pressure,repulsive forces dominate hydrogen gas.

$A$ certain quantity of real gas occupies a volume of $0.15 \ dm^3$ at $100 \ atm$ and $500 \ K$ when its compressibility factor is $1.07$. Its volume at $300 \ atm$ and $300 \ K$ (when its compressibility factor is $1.4$) is $........ \times 10^{-4} \ dm^3$ (Nearest integer).

In a $P$ versus $V$ graph,the horizontal line is found in which region?

One of the assumptions of the kinetic theory of gases is that there is no force of attraction between the molecules of a gas. State and explain the evidence that shows that this assumption is not applicable for real gases.