calculate the ksp value

Question

(a) The molar solubility of PbBr2 at 25 oC is 1.0x10-2 mol/L. Calculate Ksp. (b) If 0.0490 g of AgIO3 dissolves per liter of solution, calculate the solubility product constant. (c) Using the appropriate Ksp value from Appendix IV, calculate the pH of a saturated solution of Ca(OH)2.

Answer 1

PbBr₂(s) <==> Pb²⁺(aq) + 2Br^-(aq)

Ksp = [Pb²⁺][Br^-]²

[Pb²⁺] = 1.0x10^-2 M

[Br^-] = 2 x 1.0x10^-2 M = 2.0x10^-2 M

Ksp = (1.0x10^-2)(2.0x10^-2)²

Ksp = 4.0x10^-6

AgIO₃(s) <==> Ag⁺(aq) + IO₃^-(aq)

molar mass AgIO₃ = 283 g / mole

Concentration of AgIO₃ = 0.0490 g / L x 1 mol / 283 g = 1.73x10^-4 mol / L = 1.73x10^-4 M

Ksp = [Ag⁺] [IO₃^-] = (1.73x10^-4 )²

Ksp = 3.00x10^-8

Can't solve (c) since we don't have the Ksp value from Appendix IV