On increasing the temperature, the rate of the reaction increases because of:

Options

A. Decrease in the number of collisions
B. Decrease in the energy of activation
C. Decrease in the number of activated molecules
D. Increase in the number of effective collisions

Answer

**Step-by-Step Solution:**

1. **Understanding the Effect of Temperature on Reaction Rate:**
- When the temperature of a reaction is increased, the kinetic energy of the reactant molecules also increases. This means that the molecules move faster.

2. **Collision Theory:**
- According to collision theory, for a reaction to occur, reactant molecules must collide with each other. The rate of reaction is directly proportional to the number of effective collisions per unit time.

3. **Increased Energy and Activation Energy:**
- As temperature increases, more molecules have sufficient energy to overcome the activation energy barrier. The activation energy is the minimum energy required for a reaction to occur.

4. **Increase in Number of Effective Collisions:**
- With more molecules having energy greater than the activation energy, the number of effective collisions increases. Effective collisions are those that lead to the formation of products.

5. **Conclusion:**
- Therefore, the rate of reaction increases with temperature due to an increase in the number of effective collisions, as more molecules are able to collide with enough energy to react.

**Final Answer:**
The rate of reaction increases with temperature because of an increase in the number of effective collisions.

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