(a) For the following reactions, prepare a diagram showing log(concentration) versus pH for all species in the pH range 2 to 12 for a solution made by dissolving 0.025 mol CuSO4 in 1.00 L. Equilibrium constants apply at μ = 0.1 M, which you shouldassume is constant. Do not use activity coefficients, because the equilibrium constants already apply at 0.1 M.


Remember that pH = - log[H+] γH+and [OH-] = Kw /[H+]. Use γH+ = 0.78 for this problem. From the mass balance for sulfate, find an expression for [SO42-] in terms of [Cu2+] and [H+]. Set up a spreadsheet with pH values between 2 and 12 in column A. From pH, [H+] and [OH-] in columns B and C. Guess a value for [Cu2+] in column D. From [H+] and [Cu2+], calculate [SO42+] from the equation derived from the mass balance for sulfate. From [H+], [OH-], [Cu2+], and [SO42+], calculate all other concentrations by using equilibrium expressions. Find the total concentration of Cu by adding the concentrations of all the species. Use Solver to vary [Cu2+] in column D so that the total concentration of copper is 0.025 M. You need to use Solver for each line in the spreadsheet with a different pH.
(b) Find the pH of 0.025 M CuSO4 if nothing is added to adjust the pH. This is the pH at which the net charge is 0.
(c) At what pH does each of the following salts precipitate from 0.025 M CuSO4?