The S^2- ion is a relatively strong base with an equilibrium constant of 7.7x10^-1.

What is the Ka value for HS- ?

I got the equation HS^- <-> H^+ + S^-2. Am I able to find [S^-2] with the Keq?

4 answers

I think Ka = Kw/Kb. I'm not sure what you mean by S%2= ion has eq const of 0.77. Is that Kb?
S^-2 ion has equilibrium constant of 7.7x10^-1

So it's just (1.00x10^-14)/(0.77)=1.3x10^14 = Ka HS^- ?
If the equilibrium constant is the same as Kb, yes. But I'm not sure that it is. I've never seen an ION shown as an equilibrium constant.
Alright, thanks! It's the correct answer on the answer key.