A saturated solution of iron(II) hydroxide has a molar solubility of 3.65 x 10^-6 M. Calculate the Ksp for Fe(OH)2.
Ksp = [A]^a^b
The Attempt at a Solution
Fe(OH)2 --> Fe^2+ + 2OH-
Ksp = [3.65 x 10^-6 M] * (2*[3.65 x 10^-6 M])^2
This, however, doesn't yield an answer. The professor's answer is equivalent to
[3.65 x 10^-6 M] * ([3.65 x 10^-6 M])^2
I'm assuming this is an error on his part because the concentration of hydroxide ions should be twice the concentration of iron ions, not the same.