Question

Which of the following statements is incorrect regarding physisorption?
(a) It occurs because of van der Waals forces.
(b) More easily liquefiable gases are adsorbed readily.
(c) Under high pressure it results into multi molecular layer on adsorbent surface.
(d) Enthalpy of adsorption (ΔH_adsorption) is low and positive.

Answer 1

(d) : Physical adsorption is an exothermic process (i.e., ΔH = –ve) but its value is quite low because the attraction of gas molecules and solid surface is weak van der Waals forces.