# Will magnesium fluoride be more soluble in acidic solution?

Mar 30, 2017

We assess the equilibrium:

$M g {F}_{2} \left(s\right) r i g h t \le f t h a r p \infty n s M {g}^{2 +} + 2 {F}^{-}$

#### Explanation:

This site gives a ${K}_{\text{sp}} = 5.16 \times {10}^{-} 11$. However, in acidic solution, we substantially reduce the concentration of one of the reagents that participates in the solubility expression, i.e. we modify $\left[{F}^{-}\right]$.

${F}^{-}$ 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 $M g {F}_{2}$ to a good approximation.

And thus $M g {F}_{2}$ is expected to exhibit greater solubility in acidic solution.