According to the colliison theory, most molecular colliisons do not lead to reaction. Which of the following is`//are` necessary for colliisons to successfully lead to reaction ?

Options

A. The total kinetics energy of the collision must be greater than some minimum value.
B. A catalyst must be present at the collision.
C. The colliding particles must be properly oriented in space when they collide.
D. None of these

Explanation

To determine the necessary conditions for molecular collisions to successfully lead to a reaction according to the collision theory, we can analyze the given options step by step.

### Step 1: Understand the Collision Theory
The collision theory states that for a reaction to occur, reactant molecules must collide with each other. However, not all collisions result in a reaction.

### Step 2: Analyze Option A
**Statement A:** The total kinetic energy of the collision must be greater than some minimum value (activation energy, Ea).
- **Explanation:** This is true. The kinetic energy of the colliding molecules must be sufficient to overcome the activation energy barrier for a reaction to occur. If the energy is below this threshold, the collision will not result in a reaction.

### Step 3: Analyze Option B
**Statement B:** A catalyst must be present at the collision.
- **Explanation:** This statement is false. While a catalyst can increase the rate of a reaction by lowering the activation energy, it is not a requirement for a reaction to occur. Many reactions can proceed without a catalyst.

### Step 4: Analyze Option C
**Statement C:** The colliding particles must be properly oriented in space when they collide.
- **Explanation:** This is also true. Proper orientation is crucial for effective collisions. If the molecules are not aligned correctly, even if they collide with sufficient energy, they may not react.

### Conclusion
Based on the analysis:
- **Necessary conditions for a successful reaction:**
- Option A (activation energy must be met) is necessary.
- Option C (proper orientation of colliding particles) is necessary.
- **Option B (presence of a catalyst) is not necessary.**

Thus, the correct answers are **Option A and Option C.**