Hey guys,

I was hoping you could help me out with a problem.

The question reads,

"What is the solubility of silver sulphide in pure water? HINT: This is actually an acid-base equilibrium situation involving a diprotic acid and combined equilibria. Ksp (Ag_{2}S) = 6 x 10^{-50} M^{3}"

When I first looked at it, I thought it was a simple solubility question.

Ag_{2}S dissociates into 2Ag^{+} and S^{2-}

and using an ICE table and the Ksp, you figure out the solubility.

however my prof keeps talking about how you need to combine equilibria, solve 6 unknowns using 6 equations, etc.

so i get the feeling there is more to this question (plus its out of 15 marks...)

i know that i can find the Ka for the dissociation of diprotic H_{2}S, etc.

but my intuition still tells me that solubility is related to Ksp and since i'm given Ksp, i can just find solubility using an ICE table, etc...

can anyone point me in the right direction?

thanks in advanced.