Which of the following is incorrect for chemisorption ?

Q: Which of the following is incorrect for chemisorption ?

Which of the following is incorrect for chemisorption ?

Question

Accepted Answer

Chemisorption, or chemical adsorption, is a type of adsorption that involves the formation of a chemical bond between the adsorbate and the surface of the adsorbent. Let's analyze why Option 2 is the correct answer and why the other options are incorrect:

1. **Option 2: It results into multimolecular layers.**  
   This statement is incorrect for chemisorption. Chemisorption typically results in the formation of a monolayer of adsorbate molecules on the surface of the adsorbent. This is because chemisorption involves the formation of strong chemical bonds, which generally occur only at specific sites on the surface. Once these sites are occupied, no further adsorption can occur at that site, preventing the formation of multiple layers. Therefore, the statement that chemisorption results in multimolecular layers is incorrect, making Option 2 the correct choice.

2. **Option 1: It is highly specific in nature.**  
   This statement is correct for chemisorption. Chemisorption is highly specific because it involves the formation of chemical bonds, which require specific interactions between the adsorbate and the adsorbent. The specificity arises from the need for compatibility between the electronic structures of the adsorbate and the surface, which dictates the formation of chemical bonds.

3. **Option 3: It is caused by chemical bond formation.**  
   This statement is also correct for chemisorption. The defining characteristic of chemisorption is the formation of chemical bonds between the adsorbate and the surface of the adsorbent. These bonds can be covalent or ionic in nature, and they are much stronger than the physical forces involved in physisorption.

4. **Option 4: It is irreversible.**  
   This statement is generally correct for chemisorption. Due to the strong chemical bonds formed during chemisorption, the process is often irreversible. Breaking these bonds requires significant energy, making desorption difficult under normal conditions. This irreversibility is a key distinction between chemisorption and physisorption, the latter of which is typically reversible.

In conclusion, Option 2 is the correct answer because it inaccurately describes chemisorption as resulting in multimolecular layers, which is not the case. Chemisorption is characterized by the formation of a monolayer due to the specific and strong chemical bonding at the surface.