2. . If you treat the water such that the system remains saturated with respect to the pipe deposits, how
much free Pb2+ will be in the water? Calculate the concentration of free Pb2+(aq) in an aqueous solution
saturated with Pb3(PO4)2(s) (Ksp = 3 x 10-44) assuming no ionic strength effects or reactions of either ion
with water. Show your calculation.
3. According to the EPA Lead and Copper Rule (LCR), the action level for Pb in drinking water (the level
at which threat to human health requires public notification and action towards mitigation) is 15 ppb.
If you were to add enough orthophosphate to the system saturated with respect to Pb3(PO4)2(s), would
the [Pb2+] be below the action limit? Show your calculations.