Role of Desorption in the process of catalysis

Options

A. The surface is not available for the reaction to occur .
B. Making the surface available again for more reaction to occur .
C. Half of the surface is avilable for the reaction to occur.
D. all of these

Answer

### Step-by-Step Solution

1. **Understanding Desorption**:
- Desorption is the process through which a substance is released from a surface. It is the opposite of adsorption, where a substance adheres to a surface.

2. **Role of Catalysts**:
- Catalysts are substances that increase the rate of a chemical reaction without undergoing any permanent change themselves. They provide a surface for the reactants to adsorb onto, facilitating the reaction.

3. **Catalytic Action**:
- In a catalytic reaction, reactants are adsorbed onto the surface of the catalyst. This adsorption is crucial because it brings the reactants into close proximity and in the correct orientation to react.

4. **Formation of Products**:
- Once the reactants are adsorbed, they undergo a chemical reaction on the catalyst's surface, resulting in the formation of products.

5. **Importance of Desorption**:
- After the products are formed, they need to be released from the catalyst's surface. This is where desorption plays a vital role. If the products remain adsorbed on the catalyst, they will block the active sites, preventing further reactions from occurring.

6. **Making Surface Available for More Reactions**:
- Desorption allows the catalyst's surface to become available again for new reactants to adsorb. This cycle of adsorption, reaction, and desorption is essential for the continuous operation of catalytic processes.

7. **Conclusion**:
- Therefore, the role of desorption in catalysis is to make the surface of the catalyst available again for more reactions to occur, ensuring that the catalytic process can proceed efficiently.