According to the adsorption theory of catalysis, the speed of the reaction increases because:

Options

A. In the process of adsorption, the concentration of the molecules decreases at the surface of catalyst
B. Adsorption produces heat which increases the speed of the reaction
C. Adsorption lowers the activation energy of the reaction
D. Adsorption increases the activation energy of the reaction

Answer

To solve the question regarding the adsorption theory of catalysis and the reason for the increase in reaction speed, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Adsorption Theory**:
- Adsorption theory states that the catalyst increases the rate of reaction by providing a surface for the reactants to adhere to. This increases the concentration of reactants at the catalyst's surface.

2. **Analyzing the Options**:
- **Option 1**: "In the process of adsorption, the concentration of the molecule decreases at the surface of the catalyst."
- This option is incorrect because adsorption leads to an increase in the concentration of reactants at the catalyst's surface, not a decrease.

- **Option 2**: "Adsorption produces heat which increases the speed of reaction."
- This option is correct. When molecules adsorb onto the surface of the catalyst, bonds are formed, and energy is released in the form of heat. This release of energy can increase the kinetic energy of the surrounding molecules, thereby increasing the reaction rate.

3. **Conclusion**:
- Based on the analysis, the correct answer is that the speed of the reaction increases because adsorption produces heat, which in turn increases the speed of the reaction.

### Final Answer:
According to the adsorption theory of catalysis, the speed of the reaction increases because adsorption produces heat which increases the speed of reaction.

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