Chemical equilibria of nickel chloride in HCl solution at 25 °C

Abstract

Chemical equilbria of nickel chloride in HCl solution at 25°C were analyzed by considering chemical equilibria, mass and charge balance equations. The activity coefficients of solutes were calculated by using Bromley equation. The necessary thermodynamic properties, such as the equilibrium constant for the formation of NiCl+ at zero ionic strength and interaction parameter, were evaluated by applying Bromley equation to the stability constant data reported in the literature. It was found that most nickel exists as Ni2+ in HCl solution up to 5 molality HCl. The pH values of NiCl2-HCl-H2O system at 25°C calculated in this study agreed well with the pH values measured by employing pH meter.