UNDERSTANDINGS

• R3.2.12—The hydrogen half-cell H+(aq) + e− ⇌1/2 H2(g) is assigned a standard electrode potential of zero by convention. It is used in the measurement of standard electrode potential, E⦵.

  • Interpret standard electrode potential data in terms of ease of oxidation/reduction.

• R3.2.13—Standard cell potential, E⦵ cell, can be calculated from standard electrode potentials. E⦵ cell has a positive value for a spontaneous reaction.

• R3.2.14—The equation ΔG⦵ = − nFE⦵ cell shows the relationship between standard change in Gibbs energy and standard cell potential for a reaction.

  • Determine the value for ΔG⦵ from E⦵ data.

• R3.2.15—During electrolysis of aqueous solutions, competing reactions can occur at the anode and cathode, including the oxidation and reduction of water.

  • Deduce from standard electrode potentials the products of the electrolysis of aqueous solutions.

• R3.2.16—Electroplating involves the electrolytic coating of an object with a metallic thin layer.

  • Deduce equations for the electrode reactions during electroplating.

MAKING CONNECTIONS