Electrolysis of Water — Overview & Application

Water Electrolysis Importance

Electrolysis is the process in which an electric current is applied to a system to create a chemical change. Often, electrolysis experiments are carried out in aqueous electrolyte solutions. The electrolytes are present to carry the electric charge. However, if the electrolytes are less reactive or less likely to undergo oxidation/reduction than water, the water will undergo electrolysis.

Electrolysis of water

In an electrolytic cell, water or $H_2O$ will undergo oxidation at the anode and reduction at the cathode.

At the anode: $$2H_2O(l) \rightarrow O_2(g)\ +\ 4H^+(aq)\ + 4e^-$$

At the cathode: $$4H_2O(l)\ +\ 4e^- \rightarrow 2H_2(g)\ +\ 4OH^-(aq)$$

Total cell reaction: $$6H_2O(l) \rightarrow 2H_2(g)\ +\ O_2(g)\ +\ 4H^+(aq)\ +\ 4OH^-(aq)$$

During this process water decomposes into hydrogen and oxygen gas. Because gases are formed, the reaction is indicated by bubbles forming at the electrodes.

(Video) Electrolysis of Water - Electrochemistry

by The Organic Chemistry Tutor

In this video, The Organic Chemistry Tutor explains the electrolysis of water. He starts by illustrating the experimental set-up. Then, he demonstrates the half-reactions and calculates the electric potential. After watching this video, you have a great understanding of water electrolysis!