Electrolysis

What is Electrolysis?

Within Chemistry, which covers atoms, bonding, reactions, the periodic table, organic chemistry and the chemistry of everyday life, this topic explains Electrolysis. Chemistry links what you can see in the lab to the particles and bonds behind it, so each topic here shows that link in a model.

Check that you can explain Electrolysis in your own words and give one example from everyday life. If you can do that, you have understood the core idea.

Understanding Electrolysis helps you explain why substances behave as they do, from cleaning products and food to medicines.

Electrolysis in detail

Electrolysis uses electricity to break down an ionic compound when it is molten or dissolved in water. The ions move to the electrodes: positive ions (cations) go to the negative electrode (cathode), where they gain electrons and are reduced, and negative ions (anions) go to the positive electrode (anode), where they lose electrons and are oxidised.

Molten lead bromide gives lead at the cathode and bromine at the anode. Aluminium is extracted from molten aluminium oxide dissolved in cryolite with carbon anodes. Electrolysis is used to extract and purify metals and to produce chemicals, and it needs substantial electrical energy.

How the interactive helps you understand Electrolysis

Watch the circuit in the interactive. Use any sliders or buttons it offers to change the values and see how the circuit responds.

Before you change anything, predict the result. Then change one value at a time and check whether your prediction was right. This is a quick way to build a correct mental model of Electrolysis.

Real-life uses and examples

• Use Electrolysis to explain what happens in a lab experiment and why.
• Link Electrolysis to everyday products such as cleaning agents, food and medicines.
• Read a chemical equation or diagram and work out what Electrolysis shows.

Common mistakes to avoid

• Describing what happens without explaining the particles or bonds involved.
• Mixing up the names of substances or ions when you describe Electrolysis.
• Learning the definition without testing it. Use the quiz and the interactive to check that you can apply the idea.