The minimum energy a molecule should possess in order to enter into a fruitful collision is known as:

Options

A. Reaction energy
B. Collision energy
C. Activation energy
D. Threshold energy

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the term that describes the minimum energy a molecule must have to engage in a successful collision that leads to a reaction.

2. **Defining a Fruitful Collision**: A fruitful collision refers to an effective collision, which means that the colliding molecules have sufficient energy and proper orientation to result in a chemical reaction.

3. **Identifying the Required Energy**: The minimum energy required for a collision to be effective is crucial. This energy is necessary for the reactant molecules to overcome the energy barrier that separates reactants from products.

4. **Introducing the Concept of Threshold Energy**: The minimum energy needed for reactants to undergo a reaction is known as the threshold energy. This energy is essential for the molecules to collide effectively and result in a reaction.

5. **Explaining the Energy Profile**: If we visualize the energy changes during a reaction through an energy vs. reaction coordinate graph, the threshold energy is represented as the energy required to reach the transition state from the reactants.

6. **Distinguishing Between Activation Energy and Threshold Energy**:
- Activation Energy: This is the minimum energy needed to initiate a reaction by overcoming the energy barrier.
- Threshold Energy: This encompasses the activation energy plus any additional kinetic energy that the reactants must possess to collide effectively.

7. **Conclusion**: Therefore, the term that describes the minimum energy a molecule should possess to enter into a fruitful collision is known as the **threshold energy**.

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