Current Flow in an Electrochemical Cell: Thermodynamic arguments permit the feasibility of overall cell reactions to be predicted, but give no information on rates. To understand the latter it is necessary to consider the effects on various parts of the cell of forcing the cell voltage to assume a value different from that of the equilibrium potential Eeq (V) or electromotive force (emf). In the example of Figure 1, the cell contains hydrochloric acid as aqueous electrolyte and it divides into two compartments by a semipermeable membrane. In one compartment, hydrogen is dissolved and in the other one chlorine gas is fluxed, while two platinum foils act as electrodes.
