How to Calculate the Ksp of PbCl2

Question

The solubility of PbCl2 in water is 1.62*10^(-2)

Calculate the Ksp of PbCl2 assuming that there are no other reactions but the Ksp reaction.

--Thanks for any help

Answer 1

Solubility of PbCl2 in water is 1.62 x 10-2 M (mol/L)
Find Ksp of PbCl2

1)Write out equation/expression:

PbCl2     <-->     Pb(+2)   + 2Cl(-)

**notice the molar ratios

2)Write out Ksp expression:

Ksp = [Pb+2] [Cl-]^2

3)Find the concentrations of each ion:

[Pb+2] = 1.62 x 10^-2 M
[Cl-] = 2(1.62 x 10^-2)
      = 3.24 x 10^-2 M

4)Substitute concentrations into the Ksp expression and solve:

Ksp = [Pb+2] [Cl-]^2
Ksp = [1.62 x 10-2]x[3.24 x 10-2]^2
Ksp = 1.70 x 10^-5