which one of the following is not applicable to chemisorption ?

Options

A. Heat of adsorption is negative
B. it takes place at high temperature
C. it is reversible
D. It forms mono- molecular layer

Answer

To determine which of the following statements is not applicable to chemisorption, we will analyze each option one by one:

1. **Heat of adsorption is negative**:
- Chemisorption involves the formation of chemical bonds between the adsorbate (the substance being adsorbed) and the adsorbent (the surface). This process releases energy, making it exothermic. Therefore, the heat of adsorption is indeed negative.
- **Conclusion**: This statement is applicable to chemisorption.

2. **Takes place at high temperature**:
- Chemisorption typically requires higher temperatures because it involves breaking bonds and forming new chemical bonds, which necessitates a significant amount of activation energy. Thus, it is correct that chemisorption takes place at high temperatures.
- **Conclusion**: This statement is applicable to chemisorption.

3. **It is reversible**:
- Chemisorption is characterized by the formation of strong chemical bonds, which are generally not easily broken. This makes chemisorption a non-reversible process. Therefore, stating that it is reversible is incorrect.
- **Conclusion**: This statement is not applicable to chemisorption.

4. **It forms a monomolecular layer**:
- Chemisorption typically results in the formation of a monomolecular layer of adsorbate on the surface of the adsorbent. This is because each molecule of the adsorbate forms a bond with the surface, leading to a single layer.
- **Conclusion**: This statement is applicable to chemisorption.

Based on the analysis above, the statement that is not applicable to chemisorption is:

**Answer: Option 3 - It is reversible.**

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