Question

In electrolysis of water, why is the volume of gas collected over one
electrode double that of the other electrode?

Answer 1

) In the electrolysis of water, the gas collected at cathode is : Hydrogen
and at Anode is :oxygen

2)The gas which is collected in double amount during the electrolysis is Hydrogen. This is because water contains two parts of element as compared to one part of oxygen element by volume.