electrolysis

what is electrolysis

Splitting an ionic compound using electricity

In molten electrolysis, what forms at the cathode?

The metal ion is reduced.

In molten electrolysis, what forms at the anode?

The non-metal ion is oxidised (usually a halogen)

In aqueous electrolysis, when is hydrogen produced at the cathode?

When the metal is more reactive than hydrogen

Which metals are less reactive than hydrogen?

Copper, silver, gold, platinum.

If Cu²⁺ is in solution, what forms at the cathode?

copper metal

What forms at the anode when a halide ion is present?

The halogen (Cl₂, Br₂, I₂)

What forms at the anode when no halide is present?

oxygen gas

Give the half-equation for hydrogen at the cathode

2H⁺ + 2e⁻ → H₂

Give the half-equation for chlorine at the anode

2Cl⁻ → Cl₂ + 2e⁻

Give the half-equation for oxygen at the anode

4OH⁻ → O₂ + 2H₂O + 4e⁻

What ions are present in any aqueous solution?

H⁺ and OH⁻ (from water)