Question

Learning Goal: To understand the relationship between precipitation and the solubility product and to be able to predict whether a substance will precipitate or not. Precipitation is the formation of an insoluble substance. For the equation AB(s)⇌A+(aq)+B−(aq), precipitation represents a shift to the left and the production of a solid. From Le Châtelier's principle, we know that when the product of the concentrations of A+ and B− gets above a certain level, the reaction will respond by shifting left to decrease the concentrations of A+ and B−. This critical level, Ksp, is a constant at a certain temperature. In this case, Q=[A+][B−]. where Q is the ion product. When Q>Ksp, precipitation occurs until Q is equal to Ksp. When Q≤Ksp, a precipitate does not form. What concentration of the lead ion, Pb2+, must be exceeded to precipitate PbCl2 from a solution that is 1.00×10−2 M in the chloride ion, Cl−? Ksp for lead(II) chloride is 1.17×10−5 . Express your answer with the appropriate units.

Answer 1