Action of a catalyst depends on:

Options

A. mass
B. solubility
C. Activation energy
D. None of these

Answer

To answer the question "Action of a catalyst depends on:", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Role of a Catalyst**:
- A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. It achieves this by providing an alternative reaction pathway with a lower activation energy.

2. **Identifying Key Factors**:
- The action of a catalyst primarily depends on its ability to lower the activation energy of the reaction. Other factors like mass and solubility may influence the effectiveness of a catalyst, but they are not the primary determinants of its action.

3. **Activation Energy**:
- Activation energy is the minimum energy required for a reaction to occur. In the presence of a catalyst, this energy barrier is reduced, allowing more reactant molecules to successfully collide and react, thus increasing the reaction rate.

4. **Conclusion**:
- Therefore, the action of a catalyst primarily depends on the activation energy. The correct answer to the question is that the action of a catalyst depends on activation energy.

### Final Answer:
The action of a catalyst depends on activation energy.

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