For which of the following gases is the value of the van der Waals constant $'a'$ expected to be the highest?

Pressure exerted by $1 \, mole$ of methane in a $0.25 \, L$ container at $300 \, K$ using van der Waals equation is ............... $atm$ (given $a = 2.253 \, atm \, L^2 \, mol^{-2}, b = 0.0428 \, L \, mol^{-1}$):

What is the correction term in the pressure for real gas in comparison to the ideal gas?

The inversion temperature $T_i \, (K)$ of hydrogen is (given van der Waal's constants $a$ and $b$ are $0.244 \, atm \, L^2 \, mol^{-2}$ and $0.027 \, L \, mol^{-1}$ respectively).

Consider the following figure. Which of the following gases show negative as well as positive deviation from the ideal gas behaviour?

The compressibility factor $Z = \frac{pV}{nRT}$ for hydrogen gas at $273 \ K$ and $1 \ atm$ pressure is