Question

Saturated solution of PbBr2 in .20M of CaBr2 solution. Ksp = PbBr2 = 4.67x10^-6

Need ionization equation and Molar solubility.

Answer 1

PbBr2 <-----------> Pb⁺² + 2Br^-

CaBr2 -----------> Ca⁺² + 2Br^-

Ksp = [Pb⁺²] [Br^-]

[Pb⁺²] = S M

[Br^-] = [S + 0.20 M]

S << 0.20 M

[Br^-] = 0.20 M

4.67 x 10^-6 = [S] [0.20]²

4.67 x 10^-6 = S [0.04]

S = 1.18 x 10^-4 M

S = molar solubility = 1.18 x 10^-4 M