The minimum amount of energy required for effective collisions between reacting particles is known as

Step 1: Analyze the question The question asks for the name of the minimum energy that colliding particles need so that a collision leads to a reaction (an "effective" collision).

Step 2: Explain the concept According to collision theory, a reaction happens only when:

1. Particles collide, and
2. They collide with the correct orientation, and
3. They have enough energy to break the existing bonds.

The minimum energy needed for the third condition is called the activation energy (Ea). Collisions with less energy than this simply bounce off without reacting.

Step 3: Check each option

• A. Activation energy: This is the minimum energy needed for an effective collision. ✔
• B. Bond energy: This is the energy needed to break (or released when forming) a particular bond. It is not the threshold for collisions.
• C. Kinetic energy: This is the energy of motion of particles. It depends on temperature, but it is not the name of the minimum threshold.
• D. Potential energy: This is stored energy due to position or composition. It is not the required collision threshold.

Step 4: Answer The correct option is A. Activation energy.

Tip: Think of activation energy as a "hill" the reactants must climb before they can roll down into products. Catalysts lower the height of the hill, and raising the temperature gives more particles enough energy to climb it. Whenever you see "minimum energy" with "reaction" or "effective collisions," think of activation energy.