Question

What is the silver ion concentration in a solution prepared by mixing 429 mL of 0.363 M silver nitrate with 411 mL of 0.506 M sodium chromate? The Ksp of silver chromate is 1.2 × 10-12

Answer 1

Ksp = [Ag⁺]² [CrO₄^2-]

Let us calculate the moles of Ag in total volume
0.429 L x 0.363 M/L / 0.84 L = 0.1853 M
Let us calculate the moles of CrO₄^2- in total volume
(0.506 mol/L)(0.411 L) / (0.84 L) = 0.2475 M

1.2 x 10^-12 = (0.2475 - x)  (0.1853 - 2x)²

If we keep most of the Ag+ gets precipitated
2x =~ 0.1853
x = ~ 0.09265

But not all of the Ag+ precipitates, so
1.2 x 10^-12 = [Ag+]² (0.2475 - 0.09265M)

1.2 x 10^-12 = [Ag+]² (0.15485)

[Ag+] = 2.7837 x 10^-6 M

Silver ion concentration in a solution is  2.7837 x 10^-6 M