Question

Write any two characteristics of chemisorptions.

Answer 1

Hint: Before writing, characteristics of chemisorption let us understand the meaning of term chemisorption. Chemisorption is one type of adsorption which involves a chemical reaction between the surface and the adsorbate. Generated new chemical bonds are at the adsorbent surface.

Complete Step by step solution:
Chemisorption involves the transfer, exchange, or sharing of electrons between adsorbates and adsorbents (atoms or molecules), and the adsorption of adsorbates on adsorbents is due to the formation of chemical bonds between them.

Characteristics of chemisorptions:
Chemisorption process is irreversible in nature (chemisorption is irreversible because of the chemical bond formed is difficult to break)
Chemisorption is an exothermic process and the process is accompanied by an increase in temperature.
The chemisorption process occurs slowly at low temperatures and occurs at a higher rate with an increase in pressure.
Chemisorptions process is directly proportional to surface area and thus increases with an increase in surface area with an increase in chemisorption
The chemisorption process involves chemical bond formation hence the enthalpy is high.
The chemisorption process requires a certain energy of activation.

Note: Chemisorption and physisorption are two different terms, don’t get confused between them. Physisorption is called physical adsorption, physisorption is a process in which the electronic structure of the atom or molecule is barely perturbed upon adsorption. And as seen earlier Chemisorption is a kind of adsorption that involves a chemical reaction between the surface and the adsorbate.