Surface tensions and thermodynamic parameters of surface formation of aqueous salt solutions: III. Aqueous solution of KCl, KBr and KI

Abstract

Surface tension of aqueous electrolyte solutions has been determined experimentally. Concentration and temperature dependence of the surface tension of three different salts has been studied. These include the chloride, bromide and iodide salts of potassium. The study was conducted at five different concentrations, i.e. 0.1, 0.5, 1.0, 1.5 and 2.0 mol dm −3, and five different temperatures ranging from 10 to 30 °C with 5 °C interval. The surface tension data were fitted into linear regression for estimation of surface excess concentration using Gibbs adsorption equation. The thermodynamic quantities of surface formation such as enthalpy and entropy were estimated from the slopes (d γ/d T) C of surface tension versus temperature plots at constant concentration. Concentration and temperature dependence of surface excess concentration and thermodynamic parameters of surface formation have been discussed.