How is the cell potential related to the reaction Gibbs energy?

The relationship between cell potential and Gibbs energy change for a reaction is defined by the equation ΔG = -νFE. In this equation, ΔG represents the change in Gibbs free energy, ν denotes the number of moles of electrons transferred in the electrochemical reaction, F is Faraday's constant (the charge of one mole of electrons), and E is the cell potential measured in volts.

The negative sign indicates that a positive cell potential (E > 0) corresponds to a spontaneous reaction (ΔG < 0), which is a fundamental principle in thermodynamics and electrochemistry. When the electrochemical cell generates a positive potential, it means the reaction can occur spontaneously, thereby releasing free energy. Conversely, if the cell potential is negative (E < 0), the Gibbs energy change will be positive, indicating that the reaction is non-spontaneous under standard conditions.

Understanding this relationship is crucial because it links thermodynamics (Gibbs energy) to electrochemical processes (cell potential), allowing us to predict whether a reaction can proceed spontaneously and to assess the efficiency of energy conversion in electrochemical cells. This concept is foundational in both physical chemistry and electrochemistry.