Question

What is the ratio of oxygen to hydrogen formed during electrolysis of water? Explain.

Answer 1

During the electrolysis of water, the ratio of oxygen to hydrogen gas formed is 1 : 2 by volume. This is because the chemical equation for the decomposition of water shows that two molecules of water yield two molecules of hydrogen gas and one molecule of oxygen gas.

\[\ce{2H2O -> 2H2 + O2}\]

Since the volume of gas is proportional to the number of molecules (Avogadro's Law), the volume of hydrogen produced is exactly twice the volume of oxygen.