Electrolysis Flashcards
What is electrolysis?
The breakdown of an ionic compound, molten or in aqueous solution, through the passage of electricity
What always happens at the anode (+) ?
Oxidation of non-metal ions
What always happens at the cathode (-)?
Reduction of metal or hydrogen ions
The more reactive a metal is…
The harder it is to reduce and the easier it is to oxidise
When is hydrogen produced at the cathode?
When the solution is aqueous and hydrogen is lower in the reactivity series than the metal
What is the only metal above hydrogen that can be produced when the solution is concentrated?
Zinc
What is produced when concentrated metal halide solutions are electrolysed?
The halide ion is oxidised at the anode, so the halogen is produced here
What happens when a dilute metal halide solution is electrolysed?
The hydroxide ion is oxidised and oxygen gas is produced at the anode
Oxidation of hydroxide ion
4OH– → 4e– + 2H2O +O2
