Question

How many layers are adsorbed in chemical adsorption?
A.One
B.Two
C.Multi
D.Zero

Answer 1

Hint: Chemisorption is a kind of adsorption which involves a chemical reaction between the surface and the adsorbate. It involves unimolecular layer formation of the adsorbate.
Adsorption is the deposition of molecular species onto the surface and there are two types of adsorption: Physical adsorption and Chemical adsorption or Chemisorption. The third type of adsorption, which is referred to, as activated adsorption is also known.

Complete step by step answer:
Chemisorption is a kind of adsorption which involves a chemical reaction between the surface and the adsorbate. New chemical bonds are generated at the adsorbent surface. Examples include macroscopic phenomena that can be very obvious, like corrosion, and subtler effects associated with heterogeneous catalysis. Adsorption is defined as the deposition of molecular species onto the surface. The molecular species that gets adsorbed on the surface is known as adsorbate and the surface on which adsorption occurs is known as adsorbent. Some common examples of adsorbents are clay, silica gel, colloids, metals etc.
An important example of chemisorption is in heterogeneous catalysis which involves molecules reacting with each other via the formation of chemisorbed intermediates. After the chemisorbed species combine (by forming bonds with each other) the product desorbs from the surface.
Thus, we know that, in the chemical adsorption, one layer is adsorbed.

Therefore, the correct answer is option (A).

Note: Due to specificity, the nature of chemisorption can greatly differ, depending on the chemical identity and the surface structural properties. Thus, the bond between the adsorbate and adsorbent in chemisorption is either ionic or covalent.