Electrolysis of Aqueous Solutions
Chemistry: AQA GCSE Higher, topic 4.4.4
Electrolysis of Aqueous Solutions
The products of the electrolysis of aqueous solutions are difficult to predict because the water molecules in the solution split up to give hydrogen (H+) and hydroxide (OH-) ions.
At the anode (positive electrode)
- What is formed at the anode depends on if there are halide ions present:
- If there are halide ions present, the respective halogen forms.
- If there are no halide ions, oxygen forms.
At the cathode (negative electrode)
- What is formed at the cathode depends on the reactivity of the metal:
- Hydrogen is produced if the metal is higher than hydrogen in the reactivity series.
- The metal is produced if the metal is lower than hydrogen in the reactivity series.
Test yourself on Electrolysis of Aqueous Solutions
Which electrode is the positive electrode during electrolysis?