The Ksp of Ag2CrO4 is 1.1 × 10–12 at 298 K. the solubility (in mol/L) of Ag2CrO4 in a 0.1 M AgNO3 solution is :
(2S + 0.1)2 × S = 1.1 × 10–12
neglecting S as compared to 0.1
S = 1.1 × 10–10
We are given the solubility product constant Ksp for Ag2CrO4 as at 298 K. We need to find its solubility in a 0.1 M AgNO3 solution.
Ag2CrO4(s) ⇌ 2Ag+(aq) + CrO42−(aq)
Ksp = [Ag+]2[CrO42−] =
The solution already contains Ag+ ions from 0.1 M AgNO3. Let the solubility of Ag2CrO4 be S mol/L. Then:
[Ag+] = 0.1 + 2S ≈ 0.1 M (since S is very small)
[CrO42−] = S
Ksp = (0.1)2 × S =
0.01 × S =
S = = mol/L
The solubility of Ag2CrO4 in 0.1 M AgNO3 solution is mol/L
For a salt AxBy ⇌ xAy+ + yBx−:
Ksp = [Ay+]x[Bx−]y
Common Ion Effect: Presence of common ion decreases solubility
Solubility (S) in pure water: S =