CHEMISTRY · Single correct · AP · Chemistry · Equilibrium · Equilibrium
Problem
Lead(II) chromate has Ksp=1.2×10−13 at 25∘C. Which statement best justifies labeling this salt as “insoluble” in water?
(a) Because Ksp=1.2×10−13 is smaller than Kw, the salt must be insoluble in water.
(b) The large molar mass of PbCrO4 makes its molarity in solution extremely small, accounting for its insolubility.
(c) Its Ksp is many orders of magnitude smaller than 1, so the dissolution equilibrium strongly favors the solid phase and only a negligible amount dissolves.
(d) A low Ksp means the maximum concentration of PbCrO4 that can dissolve is exactly 1.2×10−13M, a vanishingly small amount.