A chemist constructs a galvanic cell at 298 K using a strip of magnesium metal in 1.0 M Mg2+ solution as one half-cell and a strip of lead metal in 1.0 M Pb2+ solution as the other half-cell. The two half-cells are connected by a porous glass frit that allows ion flow while preventing bulk mixing of the solutions.
(a) Describe the primary purpose of a salt bridge or porous frit in an electrochemical cell.
(b) Identify which electrode is the anode and which is the cathode for this cell. Justify your assignment in terms of standard reduction potentials.
(c) For this galvanic cell, specify the direction of migration for cations and anions through the porous frit. Explain how this movement maintains electrical neutrality in the two half-cells.
(d) Describe qualitatively how the concentrations of Mg2+ and Pb2+ change as the cell discharges. Relate these changes to the ion migration described in part (c).