Question

The correct statement regarding chemisorption is

• A. It is a multilayered adsorption
• B. The process is reversible in nature
• C. The process is not specific in nature
• D. Enthalpy of adsorption is in the range of 80-240 kJ mol\(^{-1}\)

Hint:

Chemisorption involves the formation of strong chemical bonds and is specific to the adsorbent. The enthalpy of adsorption is relatively high compared to physisorption.

Answer 1

The Correct Option is D

Chemisorption refers to the process where the adsorbate forms strong chemical bonds with the adsorbent. 
It involves a single layer of adsorbate and is generally specific to the adsorbent. The key characteristics of chemisorption are: 
Step 1: Unlike physisorption (which is multilayered), chemisorption involves a single layer of adsorption. Therefore, statement (1) is incorrect. 
Step 2: Chemisorption is not typically reversible, as the bonds formed are strong. Therefore, statement (2) is incorrect. 
Step 3: Chemisorption is highly specific in nature, as it involves the formation of chemical bonds. Thus, statement (3) is incorrect. 
Step 4: The enthalpy of adsorption for chemisorption typically lies in the range of 80-240 kJ/mol, which is consistent with the high energy of bond formation in this process. Thus, statement (4) is correct.

Answer 2

Chemisorption, also known as chemical adsorption, involves the chemical bonding between the adsorbate and the surface of the adsorbent. This type of adsorption is characterized by a number of distinct properties:

• Multilayer vs. Monolayer: Chemisorption typically results in a monolayer of adsorbate on the surface, unlike physisorption which can form multilayered adsorption.
• Reversibility: The process is largely irreversible due to the strong chemical bonds formed, contrasting with physisorption which is generally reversible.
• Specificity: Chemisorption is highly specific, as it involves the formation of chemical bonds that depend on the nature of the surface and the adsorbate.
• Enthalpy of Adsorption: Chemisorption involves higher enthalpy changes, typically in the range of 80-240 kJ mol\(^{-1}\), indicating the formation of strong chemical bonds.

Given these properties, the correct statement about chemisorption is:

Enthalpy of adsorption is in the range of 80-240 kJ mol\(^{-1}\).