Proposed new electrolytic conductivity primary standards for KCl solutions

Abstract

An absolute determination of aqueous electrolytic conductivity has been made for 0.01 molal (m) and 0.1 m potassium cliloride solutions, over the temperature range of 0 to 50 °C in 5 degree intervals. A cell with a removable center section of accurately known length and area was used for the measurements. Values were adjusted to be in conformity with the ITS-90 temperature scale. The overall uncertainty over the entire temperature range is estimated to be 0.03%. Values at 25 °C for 0.01 and 0.1 m are 0.00140823 and 0.0128246 S/cm, respectively. It is proposed that these values be adopted as primary standards for aqueous electrolytic conductivity, replacing the demal scale.

Molality-based primary standards of electrolytic conductivity (IUPAC Technical Report)

“…8-11 are presented in Table 2. The values of κ calculated using these parameters are identical to those originally published [7]. The original conductivities were calculated using eq.…”

“…temperature range from 0 to 50°C, the relationship between t on the ITS-90 and t 68 , the Celsius temperature on the IPTS-68, is given by (6) The correction was performed using eq. 7, where κ is the corrected electrolytic conductivity (ITS-90), κ 68 is the originally measured conductivity (IPTS-68), and b 68 , c 68 , as well as d 68 are the parameters from the originally published polynomial fit [7]:…”

“…Parameters presented here for the aqueous solutions of KCl of molality 0.01 and 0.1 mol/kg are recalculated (see text) from the original values [7] referred to the IPTS-68 for the Celsius temperature. temperature range from 0 to 50°C, the relationship between t on the ITS-90 and t 68 , the Celsius temperature on the IPTS-68, is given by (6) The correction was performed using eq.…”

“…Further details are given in the original references [6][7][8]. Conductivity measurements for the new primary standards of molality 0.01 and 0.1 mol/kg [6,7] were performed in a Jones-type cell with a removable center extension tube. The cell is depicted in Fig.…”

“…Recently, absolute determinations of electrolytic conductivity have been performed at the National Institute of Standards and Technology (NIST), USA, of solutions of known molality in the temperature range 0 to 50 °C at intervals of 5 K [6][7][8]. These determinations were performed using a conductivity cell with a well-defined geometry.…”