Question

Determine whether a precipitate form in the following reaction conditions:

a. A solution containing lead (II) nitrate is mixed with one containing sodium bromide to form a solution that is 0.0150 M in Pb(NO3)2 and 0.00350 M in NaBr. Does a precipitate form in the newly mixed solution? Ksp PbBr2 = 4.67 x 10-6 .

b. A solution containing iron (II) nitrate is mixed with one containing sodium phosphate to form a solution that is 0.0365 M in Fe(NO3)2 and 0.00485 M in Na3PO4. Does a precipitate form in the newly mixed solution? Ksp Fe3(PO4)2 = 9.36 x 10-32 .

c. The magnesium and calcium ions present in seawater ([Mg2+] = 0.059 M and [Ca2+] = 0.011 M) can be separated by selective precipitation with KOH. What minimum [OH– ] triggers the precipitation of the Mg2+ ion? Ksp Mg(OH)2 = 1.79 x 10-11 . d. A solution is 0.085 M in Ca2+ and 0.025 M in Ag+ . If selective precipitation is to be achieved using NaCl, what minimum concentration of NaCl do you need to begin to precipitate the silver ion? Ksp AgCl = 1.79 x 10-10 .