In the electrolysis of water, the water combines with electrons at the cathode and is reduced to hydrogen gas. At the anode, water gives up electrons and is oxidized to oxygen gas. The volume of the hydrogen produced is always twice the volume of the oxygen produced, because water contains two atoms of hydrogen for each atom of oxygen. Uses of electrolysis. Electrolysis plays an important part in industry.
Sodium metal is produced by the electrolysis of molten sodium chloride.
In this process, chlorine gas is produced at the anode. Both sodium metal and chlorine gas have many important industrial and chemical uses. Magnesium, aluminum, and certain other metals are produced commercially by electrolysis. Aluminum metal is made by electrolysis of alumina dissolved in the molten mineral, cryolite. Copper and other minerals are purified by electrolysis.