On autoionization and pH of liquid water

摘要

The ionization constant of water K-w (or pH) is currently determined on the proton conductivity sigma(0) which is measured at frequencies lower than 10(7) Hz. We develop the idea that the high frequency conductivity sigma(a) (similar to 10(11) Hz), rather than sigma(0) represents a net proton dynamics in water. We count the concentration c of the H3O+ and OH- ions from sigma(a) to find c to be not dependent on temperature. We conclude that spontaneous ionization of H2O molecules is not essential in water electrodynamics; the common K-w reflects the thermoactivation of the H3O+ and OH- ions from the potential of their interaction; the lifetime of a target water molecule does not exceed parts of nanosecond.