engleski

Stability Constants of Chlorocadmium Complexes in t-Butanol + Water Mixtures (wt-BuOH = 10%, 30%, and 50%) from Electromotive Force Measurements

Potentiometric method was applied in determining the stability constants ( ) of cadmium chloride complexes at different ionic strengths in t-butanol + water mixtures (with 10, 30, and 50 mass per cent alcohol) at 288.15, 298.15 and 313.15 K, respectively. Calculation of the constants was performed by graphical Leden's method and by numerical methods: orthogonal polynomials, and nonlinear regression without and with scaling (weighting). The values obtained by the method of orthogonal polynomials were used to establish thermodynamic stability constants ( ) of CdCl+, CdCl2 and CdCl3- complexes in 10 mass per cent t-butanol and 30 mass per cent at 288.15 and 298.15 K, and also at 313.15 K and in 50 mass per cent for CdCl42- complex. Based on temperature dependence for , the thermodynamic quantities were calculated for reactions forming complexes, which are endothermic and result in increased entropy. Dependences for and for thermodynamic quantities DHo and DSo on the solvent dielectric constant are presented and were compared with analogous literature data in 2-propanol + water and acetone + water mixtures.

potentiometry; cadmium chloride complexes; t-butanol + water mixtures; stability constants; thermodynamic quantities

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