Electrolysis and Electrolytic Cells Concepts Tutorial
- Electrolysis is the process in which an electric current is used to bring about an electrochemical reaction which does not occur spontaneously (Eo for the electrolytic cell is negative1).
- Electrolytic Cells convert electrical energy into chemical energy.
- Applied voltage (emf) must be greater than the emf for the spontaneous redox reaction, ie greater than Eo.
- An electrolytic cell as shown below must have:
(a) An electrolyte containing the species that will undergo electrolysis
(b) 2 Electrodes : conductors used to permit the flow of electrons in an electrochemical cell and provide surfaces at which the reactions take place.
One electrode is the anode, the other is the cathode.
(c) A power supply (a battery or power pack in the school laboratory).
(d) Wires or leads connecting the electrodes to the power supply.
- Within the electrolytic cell:
- Electrons flow from anode to cathode (electrons flow from positive to negative).
- If more than one reaction is possible, the reaction with the lowest Eo will occur.
- Mass of substance produced electrolytically is proportional to the quantity of electricity flowing.