Question

What is the ionic concentrations of Ag+ and CrO4^-2 in a saturated solution of Ag2CrO4 at 25C? Ksp of Ag2CrO4 is 1.9x10^-12 mole^3/dm^9?

Answer 1

We interrogate the solubility equilibrium:

`Ag_2CrO_4(s) rightleftharpoons2Ag^+ + CrO_4^(2-)`

Explanation:

Now we have `K_"sp"=[Ag^+]^2[CrO_4^(2-)]`, and if we call the solubility of `"silver chromate"` under the given conditions `S`, then, by the given stoichiometry, we write..........

`K_"sp"=(2S)^2xxS=4S^3`

And thus `S=""^3sqrt((1.9xx10^-12)/(4))=7.80xx10^-5*mol*L^-1`.

And thus `S_(Ag^+)=15.6xx10^-5*mol*L^-1`;

`S_(CrO_4^(2-))=7.80xx10^-5*mol*L^-1`.