“Fluoride” (sodium fluoride) solutions help reduce the incidence of tooth decay. In a compounding pharmacy, in the absen

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“Fluoride” (sodium fluoride) solutions help reduce the incidence
of tooth decay. In a compounding pharmacy, in the absence of
deionized water, a laboratory assistant prepared 1 L of a 0.05%
(0.0119 mol/L) solution of NaF with mineral water containing 14.63
mg/L of Ca2+, 0 63 mg/L of Mg2+ and 19.09 mg/L of K+. To prepare
the solution, the laboratory worker slowly added the NaF salt to
the water, under stirring.
a) will there be precipitation of CaF2 and/or MgF2 under these
conditions? Justify your answer.
b) what are the concentrations of F-, Ca2+, Mg2+ and K+ in the
aqueous phase, after equilibrium is reached?
c) if there is precipitation of CaF2, what is the mass of
precipitate formed? If there is no precipitation, how much fluoride
should be added to precipitate CaF2?
d) what is the solubility of CaF2 in pure water?
e) what is the solubility of CaF2 in 0.01 mol/L Ca(NO3)2
solution?