Question

The thermodynamic solubility product of Ag2CrO4 is 1.1x10^-12. What is the [Ag+] in a saturated Ag2CrO4 solution that is also 30 mM NaNO3?

Answer 1

Given that

Ksp for Ag2CrO4 = 1.1*10^-12

i.e. [Ag+]^2 [CrO4-] = 1.1*10^-12

Let's say, [Ag+] = 2s and [CrO4-] = s M

Therefore, (2s)^2 * s, i.e. 4s^3 = 1.1*10^-12

i.e. s = {(1.1*10^-12)/4}^(1/3) = 0.65*10^-4 M

[Ag+] (in solution of Ag2CrO4) = 2*0.65*10^-4 M​, i.e. 1.3*10^-4 M

Therefore, [Ag+] in saturated Ag2CrO4 solution having [NaNO3] as 30 mM, i.e. 30*10-^3 M is

[Ag+] (in solution of Ag2CrO4 + NaNO3) = 1.3*10-^4 M (since there is no common ion, [NaNO3] can't hamper the solubility of Ag2CrO4)