Electrolysis of Aqueous Solutions (AQA GCSE Chemistry Combined Science): Flashcards

Water produces H⁺ and OH⁻ ions that react at electrodes

H⁺ (hydrogen ions) and OH⁻ (hydroxide ions)

$\ce{H2O(l) <=> H+(aq) + OH-(aq)}$

The less reactive ion

The ion that can be oxidised more easily

Cu²⁺ (copper is less reactive than hydrogen)

Solid copper deposits on cathode

$\ce{Cu^{2+}(aq) + 2e- -> Cu(s)}$

OH⁻ ions (from water)

$\ce{4OH-(aq) -> 2H2O(l) + O2(g) + 4e-}$

Oxygen gas (O₂) and water

They remain; H⁺ ions reduced instead

Halide ions (e.g. Cl⁻)