In electrolysis of water why is the volume of gas collected over one electrode is double the other electrode?
The chemical formula of water is H2O. Thus, in a water molecule, the ratio of number of hydrogen atoms to oxygen atoms is 2 : 1. So, when water is electrolysed hydrogen and oxygen will be obtained in the ratio of 2 : 1, that is the amount of hydrogen gas obtained (at cathode) by the electrolysis of water will be twice that of oxygen gas (at anode).
