Potentiometric studies of multicomponent activity coefficients using the lanthanum fluoride membrane electrode

Abstract

The hydrogen chloride-time curve obtained in the chloridization of a typical oxide ore (reaction 2) from the Zambian Copperbelt is given by curve A of Figure 3. Curve B shows the hydrogen chloride feed to the reactor as controlled by a flow controller and a mass flow meter. Again, the hydrogen chloride partial pressure-time behavior can be readily determined from the curve. The data show that initially the rate of hydrogen chloride consumption is high, the rate then tapering off as the extent of reaction increases. Furthermore, as the hydrogen chloride feed rate is accurately known, the stoichiometry of reaction 2 can be invoked to calculate from the hydrogen chloride data the copper consumption as a function of time. Consequently, complete concentrationtime data for both reactants can be obtained, so facilitating the study of the kinetics of the reaction.Curve C of Figure 3 depicts the hydrogen chloride-time behavior obtained when the effluent from the chloridization reactor is reduced by hydrogen (reaction 3). The curve is similar to the hydrogen chloride feed curve indicating that the hydrogen chloride is regenerated by reaction 3 very much more rapidly than it is consumed in reaction 2.Accuracy and Precision. When considering the accuracy

Calculation of liquid junction potentials for equilibrium studies

“…In this case there is not only a 10-fold improvement in precision but also a dramatic change in the ^(NaF) value. Insofar as comparison is possible, the result is again in agreement with literature values (40,41).…”

Activity coefficients of NaCl in the NaCl+NaBF4+H2O ternary system at 298.15K

“…(8), we get that˛B < 0 in all cases (except for NaCl + NaClO 4 + H 2 O system where˛B → 0), which implies that log B > log 0 B , that is |log B | < |log 0 B |. In short and following the argument between Buttler and Huston [37] for the NaCl + NaF + H 2 O system, we can state that, generally speaking, Na + -X − interactions (being X: BF 4 , ClO 4 or NO 3 ) are slightly stronger than Na + -Cl − interactions. This behaviour will be argued later.…”

“…The following expression may then be derived [1][2][3]15,18,37]: Table 3 shows the values for˛B, as well as the sum of˛A +˛B, which should be practically constant ifˇA =ˇB =0. As can be observed, only if we consider the values for I > 1.0 mol kg −1 , results A +˛B ∼ = constant.…”

Solution Properties of Inorganic Contamination in Mixed Solvents: Theory, Progress, and Limitations

“…where β (0) , β (1) , and C γ are ion-interaction parameters, and are usually acquired by optimizing the experimental activity coefficient data using an iteration minimization procedure (e.g., Butler and Huston, 1970). For 1:1 electrolytes, many authors Gupta, 1979;Hernández-Luis, 2003;Kozlowski et al, 1987;Pitzer, 1973;Wang et al, 1994) have observed that β (0) (usually identified with the total binary ionic interactions) and β (1) (identified with interactions between unlike-charged ions) varied linearly as a function of the inverse solvent dielectric constant in water and mixed solvents.…”