Question

The term ‘sorption’ stands for
A. Absorption
B. Adsorption
C. Both absorption and adsorption
D. Desorption

Answer 1

Hint: Sorption comes under the branch of different chemistry called surface chemistry as it is a surface phenomenon. When 2 different molecules come in contact with one another, they try to dissolve into one another along the surface. This behaviour is studied under sorption.

Complete step by step answer:
-Sorption is a process which is used to attach 2 different substances to one another, creating a boundary called interface. There are 3 cases of sorption – absorption, adsorption and ion exchange.
-Adsorption is the process in which the ions and molecules from a substance bond or adhere to a surface of another phase. Eg adsorption of molecules to the polymer surface.
Absorption is a physical process in which a substance is dissolved in a solid or a liquid. Substance can be in any phase, solid, liquid or gas. Eg. Carbonation of beverages.
Ion exchange is simply an exchange of the ions between 2 electrolytes when present in a solution. Eg when NaOH reacts with HCl then the ions get exchanged and form NaCl and water
$NaOH+HCl\to NaCl+{{H}_{2}}O$ . It occurs only in aqueous medium and not in solid medium.
Desorption is the opposite of sorption.

-The rate of sorption can be described by Fick’s laws of diffusion. There are 2 laws of Fick. The first law states that a molecule undergoes sorption from higher concentration to lower concentration. The second law states that the concentration of the molecules change with time due to sorption and the process ends when both sides of the boundaries have attained equal concentrations of the molecules.
-Sorption is a term which is used for both absorption and adsorption. Only difference is that adsorption is surface based and absorption is volume based. They can be differentiated from one another in the following way-

ABSORPTION	ADSORPTION
It is volume or bulk phenomenon	It is surface phenomenon
Process is endothermic	Process is exothermic
Rate of the reaction is uniform	Reaction rate increases and reaches equilibrium after certain time
Process is not affected by temperature variations	Increase in temperature decreases the rate of adsorption
It is commonly used for chillers, ice production and cold storage	It has industrial uses like air conditioning, development of non-stick coatings

So, the correct answer is “Option C”.

Note: Sorption term is used when both adsorption and absorption are occurring simultaneously. When only one of them occurs, we do not call it sorption. No penetration through the surface occurs in adsorption while in absorption, molecules diffuse into the surface. Dipping of cotton is a sorption process.