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Pure Appl. Chem., 2001, Vol. 73, No. 11, pp. 1783-1793


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

K. W. Pratt, W. F. Koch, Y. C. Wu and P. A. Berezansky

National Institute of Standards and Technology, Gaithersburg, MD 20899, USA

Abstract: New values of electrolytic conductivity were determined for aqueous KCl solutions with molalities of 0.01, 0.1, and 1.0 mol/kg in the temperature range 0 to 50 °C, at 5 K intervals. Expanded uncertainties, 2uc, were also calculated in accordance with the presently accepted protocol for the treatment of uncertainty. The new conductivity values are recommended as primary standards of electrolytic conductivity based on molality. They replace the previous values, based on the nonstandard demal scale, which were determined only at 0, 18, and 25 °C. The accuracy of the technique used was evaluated by repeating the determination of the previously recommended demal-based IUPAC standards of electrolytic conductivity and through comparison with other absolute measurements.