Oxidation-Reduction Potential in Sea Water

The activity of oxygen in sea water and standard oxygen electrode potentials at a range of temperatures have been computed. Accurate values for the thermodynamic ionic product of water, Kw, found by Harned & Hamer, have been applied to the calculation of the activity of hydroxyl ion in sea water from pH measurements. The activity of water in sea water has been computed from the lowering of the freezing-point. From these data the theoretical reversible oxidation-reduction potential of sea water has been calculated. .Typical data for the irreversible potential in the pH range 1-8 have been derived from Hoar's results with which experimental determinations made by Dr Atkins agree. Thus the oxidation-reduction potential of sea water is controlled solely by the oxygen system.