The term that accounts for intermolecular force in Van der Waals equation for non-ideal gas is

Which of the following indicates a plot of compressibility factor $(Z)$ $vs$ $p$ at room temperature for helium?

For a real gas,deviations from ideal gas behavior are maximum at:

The unit of the Van der Waals constant '$a$' is .......

At $300 \ K$,one mole of a gas present in a $10 \ L$ flask exerted a pressure of $2.706 \ atm$. What is its compressibility factor $(Z)$? (Given $R=0.082 \ L \ atm \ mol^{-1} \ K^{-1}$).

$A$ gas has a compressibility factor of $0.5$ and a molar volume of $0.4 \ dm^3 \ mol^{-1}$ at a temperature of $800 \ K$ and pressure $x \ atm$. If it shows ideal gas behaviour at the same temperature and pressure,the molar volume will be $y \ dm^3 \ mol^{-1}$. The value of $x / y$ is . . . . . .
[Use: Gas constant,$R = 8 \times 10^{-2} \ L \ atm \ K^{-1} \ mol^{-1}$ ]