1 mole of a real gas is kept at high pressure of 100 bar at 300 K . If van der Waals' constant $b$ is $0.005 \mathrm{~L} / \mathrm{mol}$, what are the values of compressibility factor $Z$ of the gas and \% deviation of volume from ideality?

1 L closed flask contains a mixture of 4 g of methane and 4.4 g of carbon dioxide. The pressure inside the flask at $27^{\circ} \mathrm{C}$ is

[assume ideal behaviour of gases].

The rate of diffusion of methane at 1.0 atm pressure is twice than that of another gas ' $X$ ' kept at 1.45 atm . The molecular mass of the gas ' $X$ ' is

Which of the following gases has the maximum van der Waals' constant ' $a$ '?