The van der Waals equation for one mole of a real gas can be written as $$\left(P + \frac{a}{V^2}\right)(V - b) = RT$$. For the gases $$H_2$$, $$NH_3$$ and $$CH_4$$, the values of a in $$\text{bar L}^2 \text{mol}^{-2}$$ are 0.2453, 4.170 and 2.253 respectively. Which of the following can be inferred from the a values?

A

$$NH_3$$ can be most easily liquefied

B

$$H_2$$ can be most easily liquified

C

value of a for $$CH_4$$ is less than that of $$NH_3$$ because it has the lower molar mass

D

intermolecular forces are the strongest in hydrogen