For real gases- the relation between P- V and T is given by van der Waals equation- P - an2V2 V - nb - nRT- For the following gases CH4- CO2- O2- H2 which gas will have i highest value of a ii- lowest value of b-

where 'a' and 'b' are van der Waals' constants, 'nb' is approximately equal to the total volume of the molecules of a gas. 'a' is the measure of the magnitude of intermolecular attraction.

(i) Arrange the following gases in the increasing order of 'b' Give reason.

$O_{2}, C O_{2}, H_{2}, H e$

(ii) Arrange the following gases in the descending order of magnitude of 'a'. Give reason.

$C H_{4}, O_{2}, H_{2}$

Q. Given van der Waals constant for

N H_{3}, H_{2}, O_{2}

and

C O_{2}

are respectively

4.17, 0.244, 1.36

and

3.59

, which one of the following gases is most easily liquefied?

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For real gases, the relation between P,V and T is given by van der Waals equation, (P+an2V2)(V−nb)=nRT. For the following gases CH4,CO2,O2,H2 which gas will have (i) highest value of a (ii), lowest value of b?

The correct option is A (i) CO2, (ii) H2(i) Order of intermolecular attraction is CO2>CH4>O2>H2In CO2, intermolecular forces increases with number of electrons in a molecule.(ii) Size increases in order of H2<O2<CH4<CO2Hence, H2 will have lowest value of b.

For real gases, the relation between $P, V$ and $T$ is given by van der Waals equation, $(P + \frac{a n^{2}}{V^{2}}) (V - n b) = n R T$ . For the following gases $C H_{4}, C O_{2}, O_{2}, H_{2}$ which gas will have (i) highest value of $a$ (ii), lowest value of $b$ ?