State the role of activated complex in a reaction and state its relation with activation energy

Molecular compounds that exist in the highest energy state during a chemical reaction - also known as activated stage, are referred to as activated complex. An activated complex is an intermediary between the reactants and the products of a chemical reaction.

For a successful chemical reaction the reactants require a minimum amount of energy called the activation energy. When the reactants acquire activation energy they enter the transition stage and form the activated complex.