DETERMINATION OF THE HCL DISSOCIATION CONSTANT AT A TEMPERATURE OF 350°C AND 200 BARS OF PRESSURE BY THE POTENTIOMETRIC METHOD USING A CERAMIC ELECTRODE

Abstract

A technique has been developed for pH measurement in flow-through cells at temperatures from 175 to 350°C and pressures up to 350 bars in a nonisothermal cell consisting of a ZrO2(Y2 O3) ceramic electrode and a Ag/AgCl (2 M KCl, 25°C) flow-through reference electrode. This technique has been applied to determination of the HCl dissociation constant at 350°C and 200 bars; previously, the HCl dissociation has not been studied sufficiently reliably under these conditions. The obtained value pKdis = 2.16 ± 0.03 was used to estimate the acidity of fluids from their chemical composition at the vent of high-temperature submarine hydrothermal solutions. © Pleiades Publishing, Inc. 2006.