Question

Which of the following is a property of physisorption?
A. High specificity
B. Irreversibility
C. Non-specificity
D. None of these

Answer 1

Due to weak Van der Waals forces, physical adsorption causes the adsorbate to accumulate on the adsorbent. Between the adsorbent and the adsorbate, there is no substantial attraction or bond formation.

Complete answer:
Physical adsorption, also known as physisorption, is defined as the accumulation of gas on the surface of a solid due to weak van der Waals' forces.
Properties of physisorption:
Lack of specificity: Because the van der Waals forces are universal, a given surface of an adsorbent does not display any preference for a particular gas. The amount of gas absorbed by a material is determined by the type of the gas.
Nature: adsorption of a gas by a solid is often reversible in nature.
The adsorbent's surface area: The degree of adsorption increases as the surface area of the adsorbent increases.
Enthalpy of adsorption: Physical adsorption is an exothermic process with a low enthalpy of adsorption because the attraction between gas molecules and the solid surface is solely owing to weak van der Waals interactions.
Hence, the correct option is C. Non-specificity.

Note:
Chemical adsorption, also known as chemisorption, is the other type of adsorption. Chemisorption is different from physical adsorption in that it involves the development of chemical bonds between the adsorbent and the adsorbate. As a result, it is highly particular and irrevocable in nature. When a physical adsorption occurs at a low temperature, it might transition to chemisorption as the temperature rises.