Activity coefficient assumptions in the determination of association constants. VI. Association of thallium(I) bromide from absorbance measurements

1972 ◽  
Vol 25 (2) ◽  
pp. 311 ◽  
Author(s):  
CY Chan ◽  
MH Panckhurst

Measurements are reported of the optical absorbance of aqueous solutions of thallium(I) bromide in mixture with other electrolytes a t 25°. These measurements are similar to those previously reported1 for thallium(I) chloride and are used in conjunction with two different types of ionic activity coefficient expressions to investigate association of thallium(I) bromide. Both types of expression give a reasonable description of the experimental results but there is the same disagreement with the analysis of solubility measurements found for thallium(1) chloride.


1969 ◽  
Vol 22 (2) ◽  
pp. 317 ◽  
Author(s):  
JB Macaskill ◽  
MH Panckhurst

Precise measurements are reported of the optical absorbance of aqueous solutions of thallium(I) chloride in mixture with other electrolytes at 25�. Two types of activity coefficient expressions are used to analyse the measurements in terms of association of thallium(I) chloride. The method of analysis is similar to that used for solubility measurements1-3 and the different types of measurements lead to different values for the association constants.



1972 ◽  
Vol 25 (2) ◽  
pp. 317 ◽  
Author(s):  
CY Chan ◽  
MH Panckhurst

In an attempt to resolve discrepancies between association constants obtained from solubility and absorbance measurements for thallium(1) chloride and bromide the explicit assumptions used in the various analyses have been considered in detail. It is shown that the discrepancies can be accounted for in part by considering the activity coefficient of the complex TlCl or TIBr, and, more importantly, by allowing for the presence of small amounts of higher complexes in analysing absorbance data. It is also shown, in determining association constants using a specific ionic activity coefficient expression, that uncertainties in some interaction coefficients reduce the usefulness of our solubility measurements in non-common ion salts. In particular, it is concluded, using the specific ionic interaction coefficient expression, that association constants can at present only be arrived at from solubility measurements by specifying arbitrary interaction coefficients for thallium(1) and halide ions; and to obtain association constants using a non-specific ionic activity coefficient expression it is necessary to assume unnecessarily arbitrary subsidiary association reactions as well as an arbitrary value for the activity coefficient parameter B.



1964 ◽  
Vol 17 (5) ◽  
pp. 522 ◽  
Author(s):  
JB Macaskill ◽  
MH Panckhurst

The solubility of thallous chloride has been measured in sodium chloride and sodium perchlorate solutions at an ionic strength less than 0 1M. The association constant of thallous chloride has been determined from these measurements using two different types of ionic activity coefficient expression, one of them incorporating Br�nsted's principle of specific interaction. The method for determining the association constant gives all the parameters in the treatment but the two activity coefficient expressions give different sets of parameters. These are discussed.



1970 ◽  
Vol 14 ◽  
pp. 102-126 ◽  
Author(s):  
Frank L. Chan ◽  
W. Barclay Jones

AbstractAn x-ray spectrometer with experimental results is herewith described using a radiosotope source Fe55 having a halflife of 2.6 years. As a result of the disintegration, the managanese x-rays are capable of exciting fluorescent x-rays of such elements as sulfur, chlorine, potassium, calcium, scandium and titanium in aqueous solutions. These elements with the Ka wavelengths ranging from 5.3729 Å to 2.7496 Å may be designated as between the very soft x-rays on the one hand and the hard x-rays on the other. The x-ray spectrometer presently described has achieved a resolution of 136 ev, FWHM.Simultaneously, these elements have also been quantitatively determined by conventional x-ray fluorescent spectrometers. Since one of the spectrometers is designed to operate in vacuum as well as in helium or air, determination of sulfur, potassium and calcium were carried out in vacuum. Determination of chlorine was carried out in a helium atmosphere, Calcium, scandium and titanium were determined in air with an air-path spectrometer.In the present study aqueous solutions containing these elements were used. The use of aqueous solutions has the inherent advantages of being homogeneous and free from effect of particle size.



1975 ◽  
Vol 28 (3) ◽  
pp. 665 ◽  
Author(s):  
C Chan

The solubilities of potassium perrhenate in aqueous NaCl, KCl and KI solutions are reported. The solubility activity product for this electrolyte was determined using extrapolation functions involving three different mean ionic activity coefficient expressions. Mean ionic activity coefficients have been computed for potassium perrhenate in dilute aqueous solutions and there is no justification for considering ion association1,2 in these solutions.



1966 ◽  
Vol 19 (6) ◽  
pp. 915 ◽  
Author(s):  
JB Macaskill ◽  
MH Panckhurst

The solubility of thallous chloride has been measured in solutions of hydrochloric acid, caesium chloride, caesium perchlorate, barium chloride, and in various mixtures of sodium chloride and sodium perchlorate. These measurements are analysed to give the association constant for thallous chloride, paying particular attention to ionic activity coefficient formulae. It is shown that an activity coefficient expression which assumes no specific interactions between free ions is unsatisfactory in contrast to an expression which assumes such interactions. The consequences of this are discussed.



1969 ◽  
Vol 22 (5) ◽  
pp. 911 ◽  
Author(s):  
CW Childs ◽  
MH Panckhurst

Measurements are reported of the solubility of thallium(I) bromide in aqueous solutions of potassium bromide, sodium perchlorate, barium bromide, and of mixtures of sodium bromide and sodium perchlorate and of sodium bromide and sodium acetate at 25�. The measurements are used to test the merits of two types of ionic activity coefficient expressions, one assuming specific interactions between free ions and the other not. It is shown that neither expression can describe our results adequately, in contrast to previous solubility results with thallium(I) chloride for which the specific interaction expression was adequate.



1992 ◽  
Vol 57 (11) ◽  
pp. 2209-2214 ◽  
Author(s):  
Rajalakshmi Heyrovská

This paper brings further results on the degrees of dissociation (α) and hydration numbers (nh) of strong electrolytes in aqueous solutions at 25 °C, evaluated for the first time from osmotic coefficients (ϕ). Presented here are also the equations for the non-ideality parameters, ϕ and γ± (the mean molal ionic activity coefficient), in terms of α and nh.



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