Calculate the value of the solubility product constant for PbSO4 from the half-cell potentials. PbSO4(s) + 2e- ? Pb(s) + SO42-(aq) Eº = (-0.383) V Pb2+ + 2e- ? Pb(s) Eº = (-0.127) V These half-cell potentials are not accurate. You many imagine that they were determined by a poor experimentalist.