METASTABLE REGION OF AQUEOUS-SOLUTIONS OF POTASSIUM-CHLORIDE CONTAINING LEAD(II) IONS

The method of cooling at a constant rate was applied to determine the width of the metastable region of aqueous solutions of potassium chloride saturated at approximately 40-degrees-C and containing 0 to 0.1 wt.% Pb(NO3)2. Lead(II) ions widen the metastable region up to a Pb(NO3)2 concentration of about 0.01%, at which the solution is apparently saturated with the addition. Additional increase in the Pb(NO3)2 concentration rather makes the metastable region narrower. The experimental data are compared with published values and discussed in terms of theories. A plausible explanation of the observed dependences is based on Glasner's theory of nucleation of KCl in the presence of Pb2+ ions.