Atoms and Ions: Electrolysis

At its core, electrolysis defines a process where electricity is used to induce a chemical change, often breaking down ionic compounds into their original elements.
Electrolysis requires a liquid to conduct the electricity, termed the electrolyte. Electrolytes include high temperature molten compounds and solutions of ionic compounds.
In electrolysis, the substance to be broken down is added to water and then an electric current is applied via a positive electrode (the anode) and a negative electrode (the anode).
Positive ions migrate towards the cathode (negative electrode) where they gain electrons in a process called reduction.
On the other hand, negative ions move towards the anode (positive electrode) losing electrons in a process known as oxidation.
Recall that in electrolysis, oxidation happens at the anode (positive electrode) while reduction happens at the cathode (negative electrode). A useful way of remembering this is by using the acronym OIL RIG which stands for Oxidation Is Loss (of electrons), Reduction Is Gain (of electrons).
Electrolysis can be used in various everyday situations such as extracting metals from their ores, electroplating objects to make them more attractive and less corrosive, and creating a steady supply of chlorine gas.
The elements produced during electrolysis can be predicted through understanding the reactivity series. For instance, in the electrolysis of an aqueous solution of a salt, hydrogen is produced if the metal in the salt is more reactive than hydrogen.
Lastly, it is also important to take note of the environmental considerations associated with electrolysis. Electrolysis processes are often energy-intensive and can lead to significant carbon dioxide emissions if the electricity used is not from renewable resources.