The solubility of scandium (III) fluoride, ScF3, in pure water is 2.0x105 moles per liter. How do you calculate the value of Ksp for scandium (III) fluoride from this data?

1 Answer
Sep 12, 2017

Ksp(ScF3)=4.32×1018

We interrogate the reaction.....

Explanation:

We interrogate the reaction.....

ScF3(s)Sc3++3F

And as written, we can directly write the solubility expression, Ksp, where Ksp=[Sc3+][F]3

And we are given the solubility of ScF3 in water, 2.0×105molL1....

And thus [Sc3+]=2.0×105molL1

And [F]=3×2.0×105molL1

Capisce?

And then we input these numbers into the Ksp expression.....

Ksp=(2.0×105)×(6.0×105)3=4.32×1018

PS I have not got a good text at hand, but the values I read for Ksp for scandium fluoride seem to vary widely. I would check the source of these data.