Question

the solubility of Tl2CrO4 is 1.21*10^-6 in 0.150 M Na2CrO4. Calculate the Ksp of Thallium (I) Chromate.

Answer 1

Na2CrO4 gives [CrO42-] = 0.150 M

At equilibrium:
Tl2CrO4   <---->    2 Tl+     +          CrO42-

                     2s                 0.150+s       

Ksp = [Tl+]^2[CrO42-]
Ksp = (2s)^2*(0.150+s)
Ksp = (2*1.21*10^-6)^2*(0.150+1.21*10^-6)
Ksp = 8.78*10^-13

Answer: 8.78*10^-13