Consider a saturated solution of MgF2 with excess solid MgF2. Calculate the molar solubility of MgF2 (a) at pH 7.00 (b) at pH 2.00?

Answer 1

MgF2  <-->  Mg(2+)  +  2F(-)

  F(-)  +  H2O  <-->  HF  +  OH-

 . . . Need Ka for HF  and Kw

  use those with ...  pH = 7.00 >>>  [H+] = 1x10^-7M

b.  use with  pH = 2.00 >>> [H+] = 1x10^-2 M