Question

For real gases, the relation between P, V and T is given by van der Waals equaltion, $\left( P + \frac{an^{2}}{V^{2}} \right)(V - nb) = nRT.$ for the following gases which gas will have $\mathrm { CH } _ { 4 } , \mathrm { CO } _ { 2 } , \mathrm { O } _ { 2 }$, $H_{2}.$ (i) highest value of a (ii) lowest value of b

• A. (i) $CO_{2},(ii)H_{2}$
• B. (i) $CH_{4},(ii)CO_{2}$
• C. (i) $H_{2},(ii)CO_{2}$
• D. (i) $O_{2},(ii)H_{2}$

Answer 1

Answer: (A)

(i) $CO_{2},(ii)H_{2}$

Answer 2

: (i) order of intermolecular attraction is

$Co_{2} > CH_{4} > O_{2} > H_{2}$

In $CO_{2}$intermolecular forces increases with number of electrons in a molecule.

(ii) Size increase in order of

$H_{2} < O_{2} < CH_{4} < CO_{2}$

Hence, $H_{2}$will have lowest value of b.