Predict the Products of Electrolysis of Aqueous Solutions

Predict the Products of Electrolysis of Aqueous Solutions
Main factor: Position of ions in the electrochemical series

• Cation: The higher the position in the electrochemical series are very stable (remain as cation). Example: K⁺ and Na⁺ are never discharged in an aqueous solution in electrolysis.
• Anions: The higher the position in the electrochemical series are very stable (remain as anion). Example: F ^- and SO₄^2- are never discharged in an aqueous solution in electrolysis.

Second factor: Concentration of the electrolyte
Third factor: Types of electrode as anode
Electrolysis in Industries
A. Extraction of reactive metals

• Reactive metals: Sodium, calcium, magnesium and aluminium extract from their compounds
• Example: extraction of aluminium from aluminium oxide, Al₂O₃ (bauxite) by using cryolite, Na₃AlF₆ at 980˚C.

B. Purification of metals

• Anode: impure metal
• Cathode: pure metal
• Electrolyte: solution containing the ions of the metal to be purified
• Example: purification of impure copper metal.

C. Electroplating of metals

• Electroplating is a process of coating the surface of metal objects with a thin and even layer of another metal.
• Importance of electroplating is to prevent corrosion and improve the appearance.
• Cathode: object to be electroplated
• Anode: pure plating metal
• Electrolyte: aqueous solution contains plating metal ions