Which gas will be adsorbed maximum by charcoal ?

1. SO₂
2. O₂
3. NO
4. HCl

Dear Student,

Adsorption of a gas on the charcoal surface depends upon the critical temperature of the gas. Higher the critical temperature, greater will be the adsorption of gas on the activated charcoal. 
Critical temperature of SO₂=430 K
Critical temperature of O₂ = 154 K
Critical temperature of NO= 180 K
Critical temperature of HCl = 278 K
 Since SO₂ has highest critical temperature, therefore SO₂ will be adsorbed by charcoal the most.
Hence, the correct answer is (1)