Determination of the solubility product of Ba(IO(3))(2) by flow injection with amperometric detection

The solubility of Ba(IO(3))(2) has been determined in solutions containing a supporting electrolyte (KCl) to maintain the ionic strength in the 0-0.5 M range. The approach envisaged was based in the amperometric determination of iodine (or triiodide) generated in the reaction involving iodate in equilibrium in the saturated solutions and iodide contained in the solution carrier using a flow injection procedure, the electrode potential being maintained at +0.2 V in a wall-jet cell. The effect of the supporting electrolyte on the solubility of barium iodate was demonstrated and a good approximation of the value for the thermodynamic solubility constant of the precipitate was found by an appropriate correction of the solubility data using mean activity coefficients of barium iodate. The mean activity coefficients were estimated at each ionic strength by using the Debye-Hückel equation and the corrected solubility constant determined at 27 degrees C was found to be 2.7x10(-9) mol(3) l(-3).