Question

For real gases van der Waals equation is written as $\bigg( p + \frac{an^2}{V^2} \bigg) (V - nb) = nRT$ Where 'a' and 'b' are van der Waals constants . Two sets of gases are : (I)${ O2, CO2, H2}$ and $He$ (II) ${CH4, O2}$ and ${H2}$ The gases given in set-I in increasing order of 'b' and gases given in set-II in decreasing order of 'a', are arranged below. Select the correct order from the following :

• A. (I) ${ O2 < He < H2 < CO2 }$ (II) ${H2 > O2 > CH4 }$
• B. (I) ${ H2 < He < O2 < CO2 }$ (II) ${CH4 > O2 > H2 }$
• C. (I) ${ H2 < O2 < He < CO2 }$ (II) ${O2 > CH4 > H2 }$
• D. (I) ${ He < H2 < CO2 < O2 }$ (II) ${CH4 > H2 > O2 }$

Answer 1

Answer: (B)

(I) ${ H2 < He < O2 < CO2 }$ (II) ${CH4 > O2 > H2 }$

Answer 2

As per actual data's
sequence of Vander Wall constant (a)
$\begin{matrix}&H_{2}&&O_{2}&>&H_{2}\\\ value&0.042&&0.031&&0.026\end{matrix}$