Physical adsorption of a gaseous species may change to chemical adsorption with ______________.
(i) decrease in temperature
(ii) increase in temperature
(iii) increase in surface area of the adsorbent
(iv) the decrease in surface area of the adsorbent
The answer is the option (ii).
If temperature increases, chemical bonds start forming between the adsorbate and adsorbent. It is so because the energy for activation is reached on increasing the temperature. Hence, physical adsorption of gaseous species may change to chemical adsorption.