Gases deviate from ideal behaviour at high pressures because the gas molecules

Gases deviate from the ideal gas behaviour because their molecules

For a real gas at $25^{\circ} C$ temperature and high pressure $(99 \ bar)$,the value of the compressibility factor is $2$. The value of the Van der Waals constant '$b$' is $\times 10^{-2} \ L \ mol^{-1}$. (Nearest integer) (Given $R = 0.083 \ L \ bar \ K^{-1} \ mol^{-1}$)

In the following compressibility factor $(Z)$ versus pressure graph at $300 \, K$,the compressibility of $CH_{4}$ at pressure $< 200 \, bar$ deviates from ideal behaviour because

The van der Waals equation is valid for $......$.

$A$ gas deviates from ideal behaviour at a high pressure because its molecules