Ionic Conductivity of Selected 2:1 Electrolytes in Dilute Solutions of Mixed Aqueous–Organic Solvents at 298.15 K

Abstract

Equivalent conductivities of dilute solutions of calcium nitrate, cadmium nitrate, zinc nitrate, and calcium chloride (c < 0.0021 eq·dm−3) were measured in binary aqueous mixtures containing up to 70 wt % cosolvent (methanol, ethanol, and acetone) at 298.15 K ± 0.1. Data were treated by the Fuoss−Edelson equation, and its parameters, the limiting equivalent conductivity, Λ0, and the primary association constants, K 1 A, were evaluated. Variations in Walden products and K 1 A were interpreted in terms of ionic properties as well as solvent structure and dielectric constant.

Solution scanometry, a new method for determination of acidity constants of indicators

“…The results are very satisfactory in comparison with spectrophotometric results and previous reports. [29][30][31][32][33][34]…”

“…The test ascertained that there was no signicant difference among these methods, and the results obtained from the solution scanometric method show good agreement with the spectrophotometric results and the results reported in the literature. [29][30][31][32][33][34]…”

“…10 In this work, the solution scanometric method was introduced for the evaluation of the pK a of indicators, for the rst time and the results were compared with the spectrophotometric results obtained using the HypSpec program, a new version of the pHab program 27,28 and from the literature. [29][30][31][32][33][34] HypSpec is a new program for calculation of the pK a of ligands 35,36 and stability constants of complexes in aqueous and nonaqueous solutions, using spectrophotometric data. [37][38][39] The solution scanometric technique was introduced recently by Abbaspour et al 40 The method is based on scanning of Plexiglas® cells containing colored solutions.…”

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

“…This increased attraction is manifested as an increase in the magnitude of ion pairing between these charges and the formation of new pairs such as triple pairs that would not otherwise form in aqueous solutions. The most widely used standard methods for the determination of association constants include potentiometry (e.g., Doe et al, 1987;Gaizer et al, 1985;Mui and McBride, 1974;Višić et al, 1993Višić et al, , 1994Višić and Makjević, 1996b;Višić et al, 1999), spectrophotometry (Ghasemi et al, 2002), conductometry (e.g., D'Aprano et al, 1993;Doe et al, 1990;Evers and Knox;Gregorowicz et al, 1998Gregorowicz et al, , 1999Niazi et al, 1993aNiazi et al, , 1993bSokol et al, 2005;Srour and McDonald, 2008a), and ion-exchange equilibrium methods (Morris and Short, 1961;Patil and Sharma 1968;Pesavento and Alberti, 2000). Other methods such as specific ion electromotive force (EMF) measurements , NMR, and polarography are used under specific circumstances (Martell and Motekaitis, 1992).…”