Question

In the electrolysis of water,
a) Name the gas collected at anode and cathode
b) Why is the volume of gas collected at one electrode double than the other?
c) What would happen if dil H2SO4 is not added to water?

Answer 1

Hydrogen and oxygen respectively.
2.
Hydrogen will burn with a " squeaky pop" when treated with a burning splint. Oxygen re-lights a glowing splint.
Explanation:
At the cathode (-) water is reduced:
H2O(l)+e→1/2H2(g)+OH-(aq).
At the anode (+) water is oxidized:
H2O(l)→1/2O2(g)+2H+(aq)+2e

Answer 2

A) the gas collected at anode will be oxygen and the gas collected at cathode will be hydrogen.
B) It can be seen that volume of gas collected at one terminal is double the volume of gas collected at the other one. This is because water has 2 atoms of hydrogen peroxide 1 atom of oxygen. Therefore hydrogen will be double in volume than oxygen.
C)if diltute H2SO4 is not added to water, it will reduce it's conductivity and electrolysis will not be efficient.