Electrochemistry : Electrolytic Cells
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) + Cl2(g)
A Downs Cell is used commercially to electrolyze molten NaCl into sodium metal and chlorine gas:
Electrolysis of Water
2 H2O(l) 2 H2(g) + O2(g)
|2 H2O + 2 e- H2 + 2 OH-||E= -0.83 V|
|2 H2O O2 + 4 H+ + 4 e-||E= -1.23 V|
Electrolytic Cells with Aqueous Solutions
At an Inert Anode:
- F-, SO42-, and NO3- WILL NOT OXIDIZE!!
- In aqueous solution, WATER will oxidize:
2 H2OO2 + 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"