Answer:
Reaching activation energy is necessary because reactants require a minimum amount of energy start breaking a chemical bond.
Step-by-step explanation:
Activation energy is the minimum amount of energy required by the reactants to initiate a chemical reaction. The unit of activation energy is joule or kilo joule per mole or kilo calories per mole. Activation energy depends on temperature.
The temperature dependence of activation energy is given by Arrhenious equation. Activation energy is a threshold value of energy. For any reaction to occur this is the minimum amount of energy required.