Question

Calculate the solubility of each of the following compounds in moles per liter. Ignore any acid -base properties. Hg2 ^2+ is the cation in the reaction. a. Ag3PO4, Ksp = 1.8X 10^-18 b. Hg2Cl2, Ksp = 1.1 X 10^-18 (Show work).

Answer 1

a)

The salt dissolves as:

Ag3PO4 <----> 3 Ag+ + PO43-

   3s s

Ksp = [Ag+]^3[PO43-]

1.8*10^-18=(3s)^3*(s)

1.8*10^-18= 27(s)^4

s = 1.61*10^-5 M

Answer: 1.61*10^-5 M

b)

The salt dissolves as:

Hg2Cl2 <----> 2 Hg+ + 2 Cl-

   2s 2s

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

1.1*10^-18=(2s)^2*(2s)^2

1.1*10^-18= 16(s)^4

s = 1.62*10^-5 M

Answer: 1.62*10^-5 M