Question

Will magnesium fluoride be more soluble in acidic solution?

Answer 1

We assess the equilibrium:

`MgF_2(s) rightleftharpoons Mg^(2+) + 2F^-`

Explanation:

This site gives a `K_"sp"=5.16xx10^-11`. However, in acidic solution, we substantially reduce the concentration of one of the reagents that participates in the solubility expression, i.e. we modify `[F^-]`.

`F^-` is moderately basic (i.e. solutions of potassium fluoride gives rise to basic solutions), and would tend to be protonated in acidic solution. If we were willing to solve 2 equations in 2 unknowns, we could work out the solubility of `MgF_2` to a good approximation.

And thus `MgF_2` is expected to exhibit greater solubility in acidic solution.