The expression for threshold energy is given by which of the following?

Threshold energy = Activation Energy + energy possessed by reacting species

The correct answer is option 1. Threshold energy = Activation Energy + energy possessed by reacting species.

In a chemical reaction, before the reactant molecules can transform into products, they must overcome a certain energy barrier known as the activation energy (\(E_a\)). This energy barrier represents the minimum energy required for the reaction to proceed. However, not all molecules possess the necessary energy to overcome this barrier.

The threshold energy refers to the minimum energy that a molecule must possess in order to initiate a reaction. It includes the activation energy required to overcome the energy barrier (\(E_a\)) plus the kinetic energy possessed by the reacting species. The kinetic energy arises from the motion of the molecules and is crucial for collisions to occur effectively.

Therefore, the expression for the threshold energy is the sum of the activation energy (\(E_a\)) and the energy possessed by the reacting species. This expression ensures that the reacting molecules have sufficient energy to surpass the activation energy barrier and initiate the reaction.

Hence, the correct expression is: Threshold energy = Activation Energy + energy possessed by reacting species