What is the value of *Q* when the solution contains
2.50�10^{?3}*M* Mg2+ and 2.00�10?3*M* CO32?
?
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? ? *K*sp for lead(II) fluoride is
3.3�10^{?8} .

## Answer

Write the reaction as follows: – 2.50x103x2.00×103 – 5×106 Therefore, the value of Qis 5×10 Write the reaction as follows: [F-1- 1.0×102 M 3.3×10% [ps*](1.0×10 *)2 Therefore, the concentration of Pb2+ is 3 3x 10-M