H₂ gas is adsorbed on activated charcoal to a very little extent in comparison to easily liquefiable gases due to ____________.

Die to the presence of only two electrons, H₂ molecule has lesser intermolecular forces of attraction. So H₂ gas posses weaker van der waals forces. Therefore, (i) is wrong and (ii) is correct.

Higher the value of critical temperature, more easily a gas will be liquefiable and will be adsorbed readily. Since H₂ gas has lower value of critical temperature, it cannot be easily adsorbed on activated charcoal.

Therefore, (iii) is correct but (iv) is wrong.