Question

Removal of adsorbate from the surface of adsorbent is called
(A) desorption
(B) absorption
(C) adsorption
(D) none

Answer 1

Hint: Giving the basic definitions of desorption, absorption and adsorption can help us answer this question. But generally, we can keep in mind that sorption and desorption is exactly opposite processes.

Complete answer:
Let us see the basic definitions of all the three given processes;
Sorption-This term describes the processes as absorption and adsorption. Both the processes have equal importance in chemistry and biology as well. Only the major difference between both these processes is that; one is a surface process and other is a bulk process.
Absorption-It is a bulk process. The process involves the molecules entering the bulk or volume of the material by crossing the surfaces of other molecules.
Adsorption-It is a surface process. The molecules from either of gaseous or liquid phases are bound as a layer on the surface of solid. The molecules are called adsorbate and the surface is called adsorbent. The overall process is called adsorption.
Desorption-It is basically the opposite of adsorption primarily. Desorption occurs when the equilibrium conditions are altered thus, it is the removal of molecules from the surface where they were once adsorbed. In short, it refers to the release of substances from the surfaces.
It occurs when we either increase the temperature or lower the pressure of the substrate. Thus, removal of adsorbate from the surface of adsorbent is called desorption.

Hence, option (A) is correct.

Note: Actually, there is no need to explain for absorption as in the question, it factually describes the opposite of adsorption in a way. But still to analyse anything properly we should explain every related term.