(i) Electrolysis: It is the decomposition of a chemical compound [electrolyte] in the aqueous or fused [molten] state by the passage of direct electric current resulting in discharge of ions as neutral atoms at the respective electrodes.
(ii) Electrodes: They allow the electric current to enter or leave the electrolytic solution. The electrodes are two in number and are made of metal or carbon.
(iii) Ions: They are atoms which carry a positive or negative charge and become free and mobile when an electric current is passed through an aqueous solution of a chemical compound.
(iv) Electrolytic dissociation: The process due to which an ionic compound in the fused [molten] or in aqueous solution state dissociates into ions by the passage of electric current through it is called electrolytic dissociation.