Question

In electrolysis of water :
(a) Name the gas collected at cathode and anode.
(b) Why is volume of one gas collected at one electrode is double of
another ?
(c) Why are few drops of dil. H2
SO4
added to water ?

Answer 1

(a)Hydrogen and oxygen respectively.

Hydrogen will burn with a " squeaky pop" when treated with a burning splint. Oxygen re-lights a glowing splint.

(b)We usually perform Electrolysis to split constituents of water . Water composition is 2atoms of H and 1atom of O . Therefore H is double than O . The two electrodes collect H and O separately . We know that hydrogen composition in water is double than oxygen , so we find volume of gas collected in one electrode is double than volume of gas collected in another electrode .

(c):Electrolysis of pure water is very low because water is an covalent compound so it can't ionize to release ions. To increase the conductivity of water a few drops of sulphuric acid is added .Being a strong acid it can ionize completely to release H+ ions. These H+ ions are responsible for the conduction of electricity.