Thermodynamics of electrolyte solutions: activity coefficients of NaCl in the NaCl–NiCl2–H2O system at 25, 35, and 45 °C

1990 ◽  
Vol 68 (2) ◽  
pp. 294-297 ◽  
Author(s):  
Ch. Venkateswarlu ◽  
J. Ananthaswamy

The activity coefficients of NaCl in the NaCl–NiCl2–H2O system were estimated at 25, 35, and 45 °C and total ionic strengths of 0.5, 1.0, 2.0, and 3.0 m by an EMF method using a Na-ion selective electrode and a silver–silver chloride reference electrode. The Harned coefficients were calculated at all the temperatures studied. At 25 °C the data were analysed using the Pitzer formalism. The osmotic coefficients and the excess free energies of mixing were also calculated at 25 °C. Keywords: activity coefficients, sodium chloride, nickel chloride, Pitzer equations, thermodynamics.

1958 ◽  
Vol 36 (5) ◽  
pp. 780-788 ◽  
Author(s):  
S. N. Flengas ◽  
T. R. Ingraham

Using a silver–silver chloride reference electrode, the standard electrode potential his been established for the equilibrium Cd|Cd++ in melts containing equimolar quantities of KCl and NaCl. The experimentally obtained standard potential was greater than that calculated from theoretical thermodynamic data. This difference was attributed to the formation of a cadmium complex in the melt. A dissociation constant for the complex was calculated.The effect of temperature on the electromotive force of the silver–cadmium voltaic cell was also measured, and the heat of the cell reaction was calculated from the data. To extend the temperature range of the cadmium data, a cadmium–lead alloy was used in the higher temperature experiments. To correlate these data with those for the pure cadmium system, the activity coefficients of cadmium in the alloy were determined electrometrically using the silver–silver chloride electrode as a reference. It was found that the activity coefficients were in agreement with previously published data obtained at lower temperatures using a pure cadmium reference electrode. The activity coefficients were virtually independent of temperature but showed large positive deviations from unity when the mole fraction of cadmium was decreased below about 0.8.


1961 ◽  
Vol 39 (4) ◽  
pp. 773-784 ◽  
Author(s):  
S. N. Flengas

Using a silver – silver chloride reference electrode, the electrode potentials of the system U, UCl3(KCl, NaCl) and the redox potentials of the system Pt, UCl3, UCl4(KCl, NaCl) were measured at various concentrations of the uranium chlorides and at temperatures between 650 and 850 °C.From the results, the electrode potential of the system U, UCl4(KCl, NaCl) was calculated. In addition, the activity coefficients and partial molal properties of dilute solutions of UCl3 and UCl4 in the equimolar mixture of potassium and sodium chlorides were calculated.


1964 ◽  
Vol 42 (6) ◽  
pp. 1315-1322 ◽  
Author(s):  
R. Srinivasan ◽  
S. N. Flengas

The electrode potentials of the system Th, ThCl4 (KCl, NaCl) were measured at various concentrations of thorium chloride, and at temperatures between 670 °C and 850 °C, using a silver – silver chloride reference electrode. It was shown by a direct gravimetric method that the reaction,Th(metal) + ThCl4(melt) = 2ThCl2(in melt),postulated by previous investigators, did not take place.The activity coefficients, and the other partial molal properties of the solutions of ThCl4, in the equimolar mixture of potassium and sodium chlorides, were calculated as a function of temperature from the e.m.f. measurements.


1994 ◽  
Vol 6 (11-12) ◽  
pp. 945-952 ◽  
Author(s):  
Juozas Kulys ◽  
Jens A Munk ◽  
Thomas Buch-Rasmussen ◽  
Henrik E. Hansen

1957 ◽  
Vol 35 (11) ◽  
pp. 1254-1259 ◽  
Author(s):  
S. N. Flengas ◽  
T. R. Ingraham

Using a reversible silver – silver chloride reference electrode, described in the first paper of this series, standard electrode potentials have been established for the systems lead – lead chloride, zinc – zinc chloride, and nickel – nickelous chloride, in melts containing equimolar quantities of KCl and NaCl. Deviations from ideality were observed, and these were attributed to the formation of complexes. Dissociation constants for the complexes were calculated. The effect of temperature on the electromotive forces of the voltaic cells was also measured, and the heats of the cell reactions were calculated from the data.


1969 ◽  
Vol 52 (3) ◽  
pp. 607-609
Author(s):  
D L Sharpe

Abstract In the method described, a weighed feed sample is placed in 200 ml water, 1 ml nitric acid is added, and the chlorides present are titrated with silver nitrate. The titration is performed with a potentiometer equipped with a silver-silver chloride reference electrode a nd a silver indicating electrode. Collaborative s tudy showed that the method is more precise than the official method. An arithmetic mean for the coefficients of variations was 8.0 and 4.1, respectively, for the official and the potentiometric method.


Author(s):  
Amer Th. Al-Taee ◽  
Aws Z. Al-Hafidh

A square wave voltammetric technique coupled with three electrode detection system consist of hanging mercury drop electrode (HMDE) as working electrode, 1mm platinum wire as an auxiliary electrode (Pt-wire) and silver/silver chloride saturated potassium chloride (Ag/AgCl.sat.KCl) as reference electrode was used to determine the chlorpropamide indirectly through its interaction with valsartan, chlorpropamide gives no reduction peaks in the studied range. The effect of pH and the stability of the measurement were examined calibrations curve of chlorpropamide was constructed and the relation between current and concentration of chlorpropamide was linear with R2 value = 0.9944. The limit of detection for chlorpropamide was 4.89 x 10-9 M through its interaction with valsartan.


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