KH value for Ar(g), CO2(g), HCHO (g) and CH4(g) are 40.39, 1.67, 1.83×10–5
and 0.413 respectively. Arrange these gases in the order of their increasing solubility.
(i) HCHO < CH4< CO2 < Ar
(ii) HCHO < CO2< CH4< Ar
(iii) Ar < CO2< CH4< HCHO
(iv) Ar < CH4 < CO2 < HCHO
Option (iii) Ar < CO2< CH4< HCHO is the answer.