Step 1: Understanding the Question:
The question asks to identify the type of catalysis to which the adsorption theory primarily applies.
Step 3: Detailed Explanation:
1. Adsorption Theory of Catalysis: This theory, also known as the contact theory or the intermediate compound formation theory (in specific contexts), describes the mechanism of heterogeneous catalysis. It posits that heterogeneous catalysts function by adsorbing reactant molecules onto their surface.
2. Mechanism of Heterogeneous Catalysis:
* Reactant molecules from the gas or liquid phase are adsorbed onto the surface of the solid catalyst.
* This adsorption activates the reactant molecules, allowing them to react more readily.
* The reaction occurs on the catalyst surface.
* The product molecules then desorb from the catalyst surface, freeing up active sites for new reactant molecules.
3. Types of Catalysis:
* Homogeneous catalysis: Reactants and catalyst are in the same phase. Adsorption is not the primary mechanism here.
* Heterogeneous catalysis: Reactants and catalyst are in different phases (e.g., solid catalyst, gaseous/liquid reactants). Adsorption theory is directly applicable here.
* Auto catalysis: A product of the reaction itself acts as a catalyst.
* Induced catalysis: One reaction makes another reaction possible or faster.
Therefore, adsorption theory is applicable to heterogeneous catalysis.
Step 4: Final Answer:
Adsorption theory is applicable for heterogeneous catalysis.