Question

A solution is prepared in which a trace or small amount of Fe+2 is added to a much larger amount of solution in which the [OH]- is 1.0M*10^-2. some Fe(OH)2 precipitates. the value of Ksp for the salt is 8.0*10^-10. assuming that the hydroxide ion concentration is 1.0M*10^-2 calculate the Fe+2 concentration.

Answer 1

Ksp = (Fe^+2)(OH^-)^2 = 8.0E-10
Plug in 1.0E-2 for (OH)2 and solve for Fe^+2.

Answer 2

I got 8*10^-8
Is this correct?

Answer 3

I think so.

Answer 4

it's 8*10^-6 because the hydroxide concentration is squared. trust me, we went over this in my ap chem class (I got that originally wrong too)