Electrolysis of Acidulated Water and Copper Sulphate Solution with Copper & Platinum Electrodes

Electrolysis of Copper Sulphate Solution with Copper Electrodes

The copper sulphate in solution dissociates into copper ions and sulphate ions and water dissociates into hydrogen ions and hydroxyl ions. When current flows through the electrolyte

CUSO₄ → CU²⁺+ SO^2-

H₂O  → H⁺+ OH^–

 When current flows through the electrolyte, CU²⁺, H⁺ drift to the cathode and copper is discharged in preference to hydrogen. I.e. at cathode, copper is deposited, CU²⁺ + 2e^– →  Cu

At anode,

SO₄^2-, and OH^– move to the anode but copper ion is discharged into solution over SO₄^2- , and OH^–

CU²⁺ + 2e^– → Cu

Electrolysis of Copper Sulphate Solution with Platinum Electrodes

With platinum electrodes, during electrolysis, CU²⁺ and H⁺ drift to the cathode, and copper is discharged and deposited in preference to hydrogen. 

 At cathode, CU²⁺+ 2e^–  → Cu

At anode, OH^– is discharged and deposited in preference to hydrogen. 

 OH^– + OH^–  → 2H₂O + O₂ + 4e^–

Therefore, copper is deposited at the cathode, and oxygen gas is liberated at the anode, with a reduction in the concentration of copper sulphate solution.