JPS5550153A - Concentration meter of hydrogen ion and hydrofluoric acid - Google Patents

Abstract

PURPOSE: To simultaneously measure the concentrations of the afore-mentioned substances in a solution by accomplishing calculations with the use of the potential differences between a reference electrode (or S electrode), a hydrogen ion electrode (or H electrode) and a fluorine ion electrode (or F electrode).

CONSTITUTION: An S electrode 2, an H electrode 3 and an F electrode 4 are placed in a solution 1 to be measured so that the potential difference FH⁺ between the S and H electrodes and the potential difference E^cell between the F and H electrodes can be interchangeably measured by the action of a switch 5. Piror to the measurements, a number of liquids of known concentrations are used to measure the potential EH⁺ with respect to the hydrogen ion. From the straight line of log[H⁺] plotted against EH-, E₀H⁺(or EH⁺ at log[H⁺]=0 and SH⁺ (or the gradient of the straight line) are determined. Likewise, the values E₀F^- and SHF relating to the fluorine ions (in the above operations, the gain adjustor 6 is operated to make SH⁺ and SF^- take the same value, and at the same time the value E₀ ^cell is determined according to Equation I (wherein KHF stands for the dissociation constant of the hydrofluoric acid. Then, the liquid to be measured is poured into the cell, and EH⁺ is measured so that Equation II is used to measure the Hydrogen ion concentration [H⁺]. And, E^cell is measured so that hydrofluoric concentration [HF] is calculated with the use of Equation III.

COPYRIGHT: (C)1980,JPO&Japio