The value of Ksp for CuI is 1x10^-12. What is the solubility for CuI?

Question

Answer Choices:

1. 2.4x10^-4

2. 1.0 x 10^-4

3. 9x10^-6

4. 1x10^-6

5. 1.9x10^-4

I thought that the answer was #4, since x^2 would equal Ksp, but it wasn't. How can I accurately calculate for solubility?

Answer 1

Your thinking is correct.

Ksp=[Cu][I]

Ksp=s^2

s=1 X 10^-6

The only hitch would be the units.  This s is in moles/L.  The question may have asked for g/L.  Go back and double check.