Question

Adsorption is multilayered in the case of which type of adsorption
A. Physical adsorption
B. Chemisorption
C. Both
D. None of both

Answer 1

Hint: The process of adsorption involves the separation of a substance from one phase accompanied by its accumulation or concentration at the surface of another. There are two types of adsorption. They are Physisorption and Chemisorption.

Complete Step by Step Solution:
This question is answered based on the forces of attraction between the adsorbent and adsorbate.

In physical adsorption, the forces that exist, that is, Van der Waals forces are weak. Therefore, it forms multilayers. There exists a strong force of attraction. However, in chemisorption, the absorption is unilayer as it involves the formation of a chemical bond between adsorbate and adsorbent molecules
Hence the correct option is A.

Additional Information: In physical adsorption, there are weak van der Waals forces. Therefore, it forms multilayers. In chemisorption, adsorbate is attached by a chemical bond. In physical adsorption, the bonding between adsorbent and adsorbate is weak in van der Waal. s bonding which is due to electrostatic forces of attraction between opposite charges. As such multimolecular layers are possible. Physisorption is the adsorption of gases like hydrogen gas, nitrogen gas, etc at lower temperatures on the surface of adsorbent like charcoal are an example of this.

Note: When a gas is adsorbed on the surface of a solid by the weak intermolecular forces of attraction (van der Waals forces) without the formation of any chemical bond between the adsorbate and the adsorbent hence it is called physical adsorption. If the adsorbate is held on the surface of the adsorbent as a result of a chemical reaction forming surface compounds, it is called chemical adsorption.