  Chemical reactions involve the movement of charges, and this work presents a
mathematical model for describing chemical reactions in electrolytes. The model
is developed using an energy variational method that aligns with classical
thermodynamics principles. It encompasses both electrostatics and chemical
reactions within consistently defined energetic and dissipative functionals.
Furthermore, the energy variation method is extended to account for open
systems that involve the input and output of charge and mass. Such open systems
have the capability to convert one form of input energy into another form of
output energy. In particular, a two-domain model is developed to study a
reaction system with self-regulation and internal switching, which plays a
vital role in the electron transport chain of mitochondria responsible for ATP
generation crucial process for sustaining life. Simulations are conducted to
explore the influence of electric potential on reaction rates and switching
dynamics within the two-domain system. It shows that the electric potential
inhibits the oxidation reaction while accelerating the reduction reaction.
