A large increase in the rate of a reaction for a rise in temperature is due to

Options

A. increase in the number of collisions
B. the increase in the number of activated molecules
C. The shortening of mean free path
D. the lowering of activation energy

Explanation

To answer the question "A large increase in the rate of a reaction for a rise in temperature is due to," we will analyze the factors that influence the rate of chemical reactions, particularly focusing on temperature.

### Step-by-Step Solution:

1. **Understanding Reaction Rate**: The rate of a chemical reaction is influenced by several factors, including concentration, pressure, surface area, catalysts, and temperature.

2. **Effect of Temperature**: When the temperature of a reaction is increased, the kinetic energy of the molecules involved in the reaction also increases. This leads to more frequent and more energetic collisions between the reactant molecules.

3. **Collision Theory**: According to collision theory, for a reaction to occur, reactant molecules must collide with sufficient energy and proper orientation. The energy required for a reaction to occur is known as the activation energy.

4. **Increase in Activated Molecules**: As the temperature rises, a greater proportion of the molecules have energy equal to or greater than the activation energy. This means that more molecules are "activated" and capable of undergoing a reaction.

5. **Conclusion**: Therefore, the large increase in the rate of reaction with a rise in temperature is primarily due to the increase in the number of activated molecules. This leads to a higher frequency of effective collisions, resulting in an increased reaction rate.

### Final Answer:
The large increase in the rate of a reaction for a rise in temperature is due to the increase in the number of activated molecules.

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