What is activation energy for a chemical reaction?

Solution 32Q:

All molecules have certain minimum amount of energy.  These energy can be in the form of kinetic or potential energy. These energy can be used to undergo a chemical reaction when molecules collide. However, when the molecules are moving fast enough with a proper collision orientation,so that the kinetic energy is greater than the minimum energy barrier, then a reaction occurs. The minimum energy is required for a chemical reaction to occur is called the activation energy, Ea.

Thus,  Activation energy is defined as the energy barrier for a chemical reaction which must be overcome for the reactants to be conv