- Created by: Gregory B
- Created on: 03-04-19 11:08
Electrolysis - using an electrical current (direct current) to cause a reaction.
During Electrolysis, a current is passed through an electrolyte (Liquid/solution that can conduct electricity).
It involves a cathode (negative electrode) and anode (positive electrode)
Make sure to remember that the cations (positive ions) will be attracted to the cathode so therefore reduced and anions (negative ions) will be attracted to the anode so therefore oxidised.
Reduction- Gain of electrons.
Oxidation- Loss of electrons.
Electrolysis of Molten Ionic Solids Forms Elements.
- An ionic solid cannot be electrolysed as the ions cannot move and therefore cannot conduct electricity.
- This is why molten ionic compounds are used as they can be electrolysed because the ions can move freely and therefore conduct electricity.
- Metal ions are always reduced in electrolysis.
- Non-metal ions are always oxidised in electrolysis.
Some metals can be extracted from their ores using electrolysis.
- A good example is aluminium that is extracted from the ore bauxite by electrolysis. Bauxite contains aluminium oxide, but because it has a very high melting point, it is mixed with cryolite to lower the melting point.
- The mixture is molten so can conduct electricity.Electrolysis of Aqueous Solutions
- Aqueous = A solution containing H2O/water.
- When you electrolyse an aqueous solution, you also have to consider the ions in the water.
- Make sure you know the difference between the electrolysis of molten ionic solids and aqueous ionic compounds in solution. The rules only apply for ionic compounds in aqueous solution:
First Rule of electrolysis of aqueous solutions:…