For this problem, we’re being asked to calculate the concentration of Pb2+ needed in order to precipitate PbF2 from a 1.00 x 10-2 M F- solution.
Dissociation reaction: PbF2(s) ⇌ Pb2+(aq) + 2F–(aq)
Step 1: ICE Chart
Step 2: Ksp expression
Note that each concentration is raised by the stoichiometric coefficient
What concentration of the lead ion, Pb2+ , must be exceeded to precipitate PbF2 from a solution that is 1.00?10?2 M in the fluoride ion, F? ? Ksp for lead(II) fluoride is 3.3?10?8 .