On the autodissociation of water

Abstract

When under the influence of pressure or temperature, water behaves differently compared to other liquids. One possible explanation for such unusual behaviour is that water consists of two main groups of molecules with different properties, whose proportions vary with pressure and temperature. If this is indeed the case, it would be reasonable to consider that its molecular origin results from water’s autodissociation.

In this study, I investigated water’s autodissociation, explicitly examining how experimental variables such as the presence of electrolytes and temperature affect it and the extent to which water ions influence surrounding molecules, particularly the properties of dissolved solutes. The pH electrode was the primary experimental technique, complemented by calorimetry and ultraviolet–visible spectroscopy.

The results suggest that due to its self-ionisation, water contains a fluctuating population of molecules that propagates over time, which causes water to exhibit acidic properties. It was also shown that the autodissociation of water, and therefore the spread of this fluctuating population of molecules, is intensified by the increased kinetic energy and is an exothermic process. Hence, it is possible to control its propagation and extent of influence, which was found to significantly impact the properties of dissolved solutes, including the ultraviolet–visible spectrum of 4-nitrophenol and the biological activity of laccase.

Thus, the experimental facts reported herein show that even at a concentration as low as one-tenth of a micromole per litre, water ions propagate and exert considerable influence on dissolved solutes, supporting the so-called conjecture of “two waters”. Moreover, the experimental facts strongly support the concept according to which water is an active matrix that plays an active role in the physicochemical properties of the dissolved substances.