Question

Which of the following statement is incorrect about the nature of chemisorption?

• A. It is endothermic in nature.
• B. The extent of chemisorption first increases with temperature, then decreases.
• C. Enthalpy of adsorption is in the range of 40-400 kJ/mol.
• D. It is reversible in nature.

Hint:

Chemisorption is characterized by the formation of strong chemical bonds, making it mostly irreversible.

Answer 1

The Correct Option is D

Chemisorption refers to the process in which a gas molecule chemically bonds with a surface. The key characteristics of chemisorption are: - **(1) It is endothermic in nature:** Chemisorption typically requires energy to break bonds and form new ones, hence it is endothermic. - **(2) The extent of chemisorption first increases with temperature, then decreases:** Chemisorption increases with temperature up to an optimal point. At very high temperatures, the adsorbed molecules may desorb due to the increased kinetic energy. - **(3) Enthalpy of adsorption is in the range of 40-400 kJ/mol:** This is correct because chemisorption involves the formation of strong chemical bonds, leading to high enthalpy values. - **(4) It is reversible in nature:** This statement is incorrect. Chemisorption is typically irreversible due to the strong chemical bonds formed during the process. Thus, the incorrect statement is (4). Final Answer: \[ \boxed{\text{(4) It is reversible in nature.}} \]