Activity Coefficients of NaClO4 in (PEG 4000 + H2O) Mixtures at (288.15, 298.15 and 308.15) K

Abstract

<em>The cell potential of the cell containing two ion-selective electrodes (ISE), </em><em>Na-ISE | NaClO₄ (m), PEG 4000 (Y), H2O (100-Y) | ClO₄-ISE </em><em>has been measured at temperatures of (288.15, 298.15, and 308.15) K as a function of the weight percentage Y of PEG 4000 in a mixed solvent at a 1 Mpa and the standard state for measured activity coefficients will be a solution of the salt in pure water. Y was varied between (0 and 25) wt.% in five-unit steps and the molality of the electrolyte (m) was between 0.05 mol kg^-1 and almost saturation. The values of the standard cell potential were calculated using routine methods of extrapolation together with extended Debye-Hückel and Pitzer equations. The results obtained produced good internal consistency for all the temperatures studied. </em><em>Once the standard electromotive force was determined, the mean ionic activity coefficients for </em><em>NaClO₄</em><em>, the Gibbs energy of transfer from the water to the PEG 4000-water mixture, and the primary NaCl hydration number were calculated.</em>