Question

Calculate the molar solubility of silver phosphate in a 0.030M Na₃PO₄ solution. K_sp for silver phosphate is 8.9×10^-17.

Answer 1

Calculate the molar solubility of silver phosphate in a 0.030M Na₃PO₄ solution. K_sp for silver phosphate is 8.9×10^-17.

First, write the salt preciptiating equation

3Ag+(aq) + PO4-3(aq) <-> Ag3PO4(s)

Ksp = [Ag+]^3 * [PO4-3]

if we have already [PO4-3] = [Na3PO4] = 0.03 M

now,

substitute

8.9*10^-17 = [Ag+]^3 * (0.03)

[Ag+] = ((8.9*10^-17)/(0.03))^(1/3) = 0.00001436887 M

now,

1 mol of AG3PO4 = 3 mol of Ag

0.00001436887 mol of AG --> 1/3*0.00001436887 = 0.00000478962 M of Ag3PO4(aq) will be soluble

Ag3PO4 solubility = 4.789*10^-6 M