PH a pH of 7.3. This is clearly wrong as an acid solution should have a pH of less than 7. Treating the system as a mixture of hydrochloric acid and the amphoteric substance water, a pH of 6.89 results. A weak acid or the conjugate acid of a weak base can be treated using the same formalism. First, an acid dissociation constant is defined as follows. Electrical charges are omitted from subsequent equations for the sake of generality and its value is assumed to have been determined by experiment. This being so, there are three unknown concentrations, [HA], [H] and
Hexafluorosilicic acid 99% hydrolysis occurs and the pH drops. The rate of hydrolysis increases with pH. At the pH of drinking water, the degree of hydrolysis is essentially 100%. Neutralization of solutions of hexafluorosilicic acid with alkali metal bases produces the corresponding alkali metal fluorosilicate salts: The resulting salt NaSiF is mainly used in water fluoridation. Related ammonium and barium salts are produced similarly for other applications. Near neutral pH, hexafluorosilicate salts hydrolyze rapidly according to this equation: The majority of the hexafluorosilicic acid is converted to aluminium fluoride and cryolite. These materials are central to the conversion of aluminium ore into