Given below are two statements. Statement-I : Easily liquefiable gases are readily adsorbed Statement-II :…
Given below are two statements.
Statement-I: Easily liquefiable gases are readily adsorbedStatement-II: Adsorption enthalpy for physisorption is less compared to adsorption enthalpy for Chemisorption
The correct answer is
Both Statement-I and statement-II are correct
Both Statement-I and statement-II are not correct
Statement-I is correct but statement-II is not correct
Statement-I is not correct but statement-II is correct
Solution
(I) Easily liquefiable gases are adsorbed more easily because higher the critical temperature, higher is the intermolecular force of attraction and easier is the liquefaction.
(II) Physical adsorption is an exothermic process but its enthalpy of adsorption is low $\left(20-40 \mathrm{KJ} \mathrm{mol}^{-1}\right)$
This is because the attraction between gas molecules and solid surface is only due to weak van der Waals forces.
On the other hand, enthalpy of chemisorption is high $-240 \mathrm{~kJ} \mathrm{~mol}^{-1}$ ) as it involves chemical bond formation.