Electrolytic cell - An electrochemical cell in which electrolysis is done.

• Electrolysis - A process in which an electric current is used to decompose a compound into its elements.

The overall reaction for the electrolytic cell above is:

2 NaCl_(l) 2 Na_(l) + Cl_2(g)

A Downs Cell is used commercially to electrolyze molten NaCl into sodium metal and chlorine gas:

Downs Cell

Electrolysis of Water

2 H₂O_(l) 2 H_2(g) + O_2(g)

Half Reactions

Reduction:     (Cathode)	2 H2O + 2 e- H2 + 2 OH-		E= -0.83 V
Oxidation: (Anode)	2 H2O O2 + 4 H+ + 4 e-		E= -1.23 V

Electrolytic Cells with Aqueous Solutions

At an Inert Anode:

• F^-, SO₄^2-, and NO₃^- WILL NOT OXIDIZE!!
  • In aqueous solution, WATER will oxidize:

2 H₂O O₂ + 4 H⁺ + 4 e^-

At an Inert Cathode:

• Group I and II metal cations WILL NOT REDUCE!!
  • In aqueous solution, WATER will reduce:

2 H₂O + 2 e^- H₂ + 2 OH^-

OR, if in acidic solution:

2 H⁺ + 2 e^- H₂

Next:  "Standard-State Cell Potentials"