A DC METHOD FOR THE ABSOLUTE DETERMINATION OF CONDUCTIVITIES OF THE PRIMARY STANDARD KCL SOLUTIONS FROM 0-DEGREES-C TO 50-DEGREES-C

A new method for the absolute determination of electrolytic conductivi ty based on direct current and potentiometric measurements is describe d. The unique design of the cell uses a removable center section whose length and cross-sectional area are accurately known. Two pairs of ma tched Ag, AgCl electrodes are used in a four terminal mode of resistan ce measurement. Measurements of the electrolytic conductivity of prima ry standard potassium chloride solution using this novel dc conductanc e cell are compared with the currently adopted IUPAC and OIML recommen dations. In addition, measurements have been made of the electrolytic conductivity of a solution of potassium chloride having a molality of 1 mol/kg (mole KCl per kilogram H2O). The values so obtained over the temperature range of 0-degrees-C to 50-degrees-C arc recommended as th e new primary standards for electrolytic conductivity.