Galvanic cells and electrolysis – standard electrode potentials

ChemistryElectrochemistryAges 17–18

Galvanic cell mode: two metal electrodes sit in solutions of their own salts, joined by a wire and a salt bridge; electrons flow through the wire from the anode (the metal with the lower E°, which is oxidized and dissolves) to the cathode (whose ions are reduced and deposit), and the voltmeter reads the standard cell potential E°cell = E°(+) − E°(−) from the standard electrode potential table. Electrolysis mode: a DC power source drives electrons to the cathode; ions migrate to the electrodes, producing Cu, H₂, O₂, Cl₂ or Na depending on the solution, and the product mass follows m = M·I·t/(n·F).