Electricity and Chemistry (CIE Topic 4)

Electrolysis

the breakdown of an ionic compound, molten or in aqueous solution, by the passage of electricity

Anode (electrolytic cell)

Positive electrode

Cathode (electrolytic cell)

Negative electrode

Electrolyte

the molten or aqueous substance that undergoes electrolysis

Cathode observation molten lead bromide

Coating of grey solid (lead bromide electrolysis with inert electrodes)

Anode observation molten lead bromide

Brown gas (lead bromide electrolysis with inert electrodes)

Cathode observation concentrated hydrochloric acid

Bubbles of gas that gives "squeaky pop" on ignition (concentrated hydrochloric acid electrolysis with inert electrodes

Anode observation concentrated hydrochloric acid

Bubbles of pale yellow gas that bleaches damp litmus (concentrated hydrochloric acid electrolysis with inert electrodes)

Cathode observation concentrated sodium chloride

Bubbles of gas that gives "squeaky pop" on ignition (concentrated sodium chloride electrolysis with inert electrodes)

Anode observation concentrated sodium chloride

Bubbles of pale yellow gas that bleaches damp litmus (concentrated sodium chloride electrolysis with inert electrodes)

Cathode observation dilute sulphuric acid

Bubbles of gas that gives "squeaky pop" on ignition (dilute sulphuric acid electrolysis with inert electrodes)

Anode observation dilute sulphuric acid

Bubbles of gas that reignites glowing splint (dilute sulphuric acid electrolysis with inert electrodes)

General principle during electrolysis is

metals or hydrogen are evolved at the cathode and non-metals (excluding hydrogen) are formed at the anode

Hydrogen fuel cell inputs

hydrogen and oxygenhyd

hydrogen fuel cell outputs

water and electricity