| Abstrakt: |
The emf of the following galvanic cell is calculated on the basis of classical irreversible thermodynamics. The membrane is permeable to water, K, Na and Cl ions, but impermeable to the anion R. If the membrane consists of separate channels for transport of cations and anions, these channels being charged or neutral, the emf calculated for the present cell can be approximated by the equation which for zero transport number of Cl ions in the membrane, t′=0, gives In these equations u′ is the mobility of an ion in the membrane and C is the concentration of an ion in solution. K is the equilibrium constant for the equilibrium KCl(aq)+NaM(membrane)=NaCl(aq)+KM(Membrane). The second equation is recognized as the Goldman-Hodgkin-Katz equation for 'the membrane potential' when the membrane is cation conducting. The present equations, however, give the total emf for the galvanic cell including not negligible contributions to the cell potential from the KCl salt bridges. [ABSTRACT FROM AUTHOR] |
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