Exergic reaction

Figure 5.8 Reaction coordinate diagram for an exergic reaction in which the products are lower in energy than the reactants.

However, the Hammond postulate also holds for exergic reactions where the transition state is early and the activated complex more resembles the reactant. For such reactions changes in the energy of the reactants have the greatest effect on the energy of the transition state and thus the rate of the reaction. 

Thus, the total energy required for the reaction can be supplied by a combination of electricity and heat. The electrical power required can be reduced by operating at higher temperature. This is usually desirable, because heat is often available as a by-product and has a lower exergic value than electricity [9]. 

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