Electrolysis Flashcards

Flashcards covering key vocabulary and concepts related to electrolysis.

Electrolysis

The breaking down of a substance using electricity. An electric current is passed through an electrolyte (a molten or dissolved ionic compound), causing it to decompose.

Electrolyte

A molten or dissolved ionic compound that conducts electricity during electrolysis.

Oxidation

The loss of electrons.

Reduction

The gain of electrons.

Cathode

The negative electrode where positive ions (cations) move towards and are reduced (gain electrons).

Anode

The positive electrode where negative ions (anions) move towards and are oxidised (lose electrons).

Ionic Half Equations

Show how electrons are transferred during reactions, especially at each electrode during electrolysis.

Molten Ionic Compounds Electrolysis

Molten ionic compounds can be electrolysed because the ions can move freely, usually breaking up into their elements.

Electrolysis of Molten Lead Bromide (PbBr₂)

Example: +ve Pb2+ ions are attracted to the -ve cathode, where a lead ion accepts two electrons and is reduced to a lead atom (Pb2+ + 2e- → Pb). -ve Br- ions are attracted to the +ve anode, where two bromide ions lose one electron each and are oxidised to a bromine molecule (2Br- → Br₂ + 2e-).

Inert Electrodes

Electrodes made from an unreactive material that doesn't take part in the reaction.