caa a22 4500 477139132 CHVBK 20180405111727.0 cr unu---uuuuu 170330e19970701xx s 000 0 eng 10.1007/BF02767623 doi (NATIONALLICENCE)springer-10.1007/BF02767623 Equations for calculation of the pH of buffer solutions containing sodium or potassium dihydrogen phosphate, sodium hydrogen phosphate, and sodium chloride at 25°C [Elektronische Daten] [Jaakko Partanen, Pentti Minkkinen] Published thermodynamic data measured in aqueous mixtures of sodium or potassium dihydrogen phosphate with hydrogen phosphate and chloride at 25°C were used to test recently developed methods for calculation of the pH of phosphate buffer solutions. Equations for ionic activity coefficients are used in these methods. It is shown that all data used in the tests up to an ionic strength of about 0.5 mol-kg-1 can be accurately predicted by the two methods recommended. In one of these methods, equations of the Hückel type are used for ionic activity coefficients and in the other equations of the Pitzer type. Several sets of phosphate buffer solutions are recommended,e.g., for calibrations of glass electrode cells. In the recommended sets, the pH of the buffer solutions can be calculated either by the Hückel or Pitzer method, and the pH predictions of these methods agree in most cases within 0.005 at least up to ionic strengths of about 0.2 mol-kg-1. The pH values of the two primary pH standards endorsed by IUPAC based on aqueous mixtures of KH2PO4 and Na2HPO4,i.e., pH values of 6.865 and 7.413, can also be accurately predicted by the equations recommended in this study. Plenum Publishing Corporation, 1997 Ionic activity coefficients nationallicence phosphate buffer solutions nationallicence pH nationallicence electromotive forces nationallicence Partanen Jaakko Department of Chemical Technology, Lappeenranta University of Technology, P.O. Box 20, FIN-53851, Lappeenranta, Finland aut Minkkinen Pentti Department of Chemical Technology, Lappeenranta University of Technology, P.O. Box 20, FIN-53851, Lappeenranta, Finland aut Journal of Solution Chemistry Springer US 26/7(1997-07-01), 709-727 0095-9782 26:7<709 1997 26 10953 https://doi.org/10.1007/BF02767623 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02767623 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Partanen Jaakko Department of Chemical Technology, Lappeenranta University of Technology, P.O. Box 20, FIN-53851, Lappeenranta, Finland aut NATIONALLICENCE 700 1- Minkkinen Pentti Department of Chemical Technology, Lappeenranta University of Technology, P.O. Box 20, FIN-53851, Lappeenranta, Finland aut NATIONALLICENCE 773 0- Journal of Solution Chemistry Springer US 26/7(1997-07-01), 709-727 0095-9782 26:7<709 1997 26 10953 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer