Catalyst in a reaction

Options

A. Lowers the activation energy
B. Increases the rate of reaction
C. Both (a) and (b)
D. Initiates the reaction

Explanation

### 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 pathway for the reaction with a lower activation energy.

2. **Effect on Activation Energy**:
In a chemical reaction, the activation energy is the minimum energy required for the reactants to transform into products. When a catalyst is introduced, it lowers the activation energy needed for the reaction to occur. This means that the reactants can convert to products more easily and quickly.

3. **Graphical Representation**:
If we plot a graph with the reaction coordinate on the x-axis and energy on the y-axis, we can visualize the effect of a catalyst.
- The graph will show a peak representing the activation energy for the uncatalyzed reaction.
- With the catalyst, the peak is lowered, indicating that less energy is required for the reaction to proceed.

4. **Conclusion**:
Therefore, the catalyst not only increases the rate of reaction but also lowers the activation energy required for the reaction to occur. Based on the options provided in the question, the correct answer would be that both statements regarding the role of the catalyst are correct.

### Final Answer:
The catalyst in a reaction increases the rate of reaction and lowers the activation energy required for the reaction to proceed.