Consider the electroplating of a metal +1 cation from a solution of unknown concentration according to the half-reaction M⁺(aq) + e^–  → M(s), with a standard potential E°. When the half-cell is connected to an appropriate oxidation half-cell and current is passed through it, the M⁺ cation begins plating out at E₁. To what value (E₂) must the applied potential be adjusted, relative to E₁, if 99.99% of the metal is to be removed from the solution?