According to collision theory, rate of the reaction increases , because -
(a)Number of collision decreases
(b)Number of molecules crossing energy barrier increases
(c)Kinetic energy of molecules increases
(d)Value of rate constant increases

Options

A. Number of collision decreases
B. Number of molecules crossing energy barrier increases
C. Kinetic energy of molecules increases
D. Value of rate constant increases

Answer

To solve the question regarding the collision theory and the factors that increase the rate of a reaction, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Collision Theory**:
- Collision theory states that for a chemical reaction to occur, reactant particles must collide with each other. Not all collisions result in a reaction; only effective collisions lead to product formation.

2. **Identifying Factors Affecting Reaction Rate**:
- The rate of a reaction is influenced by the frequency of collisions and the effectiveness of those collisions. For a collision to be effective, two conditions must be met:
- The particles must collide with the proper orientation.
- The colliding particles must possess sufficient energy to overcome the activation energy barrier.

3. **Analyzing the Options**:
- **Option (a)**: "Number of collision decreases" - This is incorrect. The rate of reaction increases with an increase in the number of collisions.
- **Option (b)**: "Number of molecules crossing energy barrier increases" - This is correct. If more molecules have enough energy to overcome the activation energy barrier, the rate of reaction increases.
- **Option (c)**: "Kinetic energy of molecules increases" - While an increase in kinetic energy can lead to more effective collisions, this option does not directly address the crossing of the energy barrier, making it less relevant.
- **Option (d)**: "Value of rate constant increases" - This is not directly related to collision theory, as it focuses on effective collisions rather than the rate constant itself.

4. **Conclusion**:
- The correct answer is **(b)**: "Number of molecules crossing energy barrier increases". This option aligns with the principles of collision theory, where an increase in the number of effective collisions leads to an increased reaction rate.