Answer: Option (a) is the correct answer.
Explanation:
An exothermic reaction is defined as the chemical reaction in which heat is released.
In an exothermic reaction, energy of products is less than the energy of reactants. This means that before the reaction energy is present within the chemical bonds of the reactants.
And, during the reaction these bonds break down and excess of energy is released into the surrounding.
In an endothermic reaction, energy is absorbed by the reactants due to which energy of product formed in more as compared to the energy of reactants.
Therefore, we can conclude that energy was stored in chemical bonds BEST describes the energy involved in an exothermic chemical reaction before the reaction.
