Activity Coefficient Determinations of KCl in the KCl plus Formamide plus Water Mixed Solvent System Based on Potentiometric Measurements at 298.2 K

In this work mean activity coefficient measurements for KCl in the KCl + formamide + water system, using the potentiometric method, are reported. The electromotive force measurements were performed on a galvanic cell of the type Ag | AgCl | KCl (m), formamide (w%), H2O (1-w)% | K-ISE, in solvent mixtures containing w=(0,10,20,30, and 40)% mass percent of formamide over ionic strengths ranging from 0.0010 to 3.9578 mola <...kg(-1). Modeling of the activity coefficients of this ternary system was based on an extended Debye-Huckel equation and the Pitzer ion-interaction model. The resulting values of the mean activity coefficients, the osmotic coefficients and the excess Gibbs energy, together with Pitzer ion-interaction parameters (beta ((0)), beta ((1)) and C (I center dot) ) and Debye-Huckel parameters (a, c and d), are reported for the investigated system.