Electrolysis drives chemical reactions in ionic substances through the application of an electric current
Electrolysis is used to produce and purify materials such as copper, aluminium and chlorine on a massive industrial scale. Practical work based on electrolysis offers opportunities for students to investigate chemical reactions based on a flow of current and apply their knowledge of the reactivity series
In this video from Malmesbury Education Mr Mitchell demonstrates the electrolysis of copper chloride and sodium sulfate solutions. He uses blue litmus paper to show a positive test for chlorine at the anode and observes copper formed at the cathode. He explains how the reactivity series can be used to predict the gases that are produced at the electrodes in the electrolysis of sodium sulfate. Eye protection should be worn when using copper chloride solution, according to advice from CLEAPSS, and attention should be paid to proper ventilation when chlorine gas is produced, particularly in the event that asthma sufferers are present. Electrolysis of copper chloride solution can be carried out in a fume cupboard.
The electrolysis of aqeuous ionic solutions is also explored in this electrolysis explanation video from BBC Education. The video demonstrates the electrolysis of a range of aqueous solutions with the aid of some animation to show the movement of the ions. It also shows a range of apparatus that can be used for electrolysis including a Hoffman voltametre. The video mentions ’microscope electrolysis’ which we believe may have meant to be ‘microscale electrolysis’, although the method shown is not at microscale. You can find out more about how microscale techniques can make practical work more effective or see an example of microscale electrolysis alongside five ways to explain electrolysis.
Also check out
- Aluminium extraction – video introducing the industrial processes in aluminium extraction, with teacher notes and questions.
- Practical electrolysis – CPD article with ideas for enhancing electrolysis practical work.
- Identifying the products of electrolysis – outline of class practical investigating electrolysis of various solutions.
- Colourful electrolysis – a class practical introducing the electrolysis of brine using universal indicator to follow the reaction.
We have collated these videos of key practical experiments to support remote teaching as part of our response to Covid-19. Teachers requested resources to help them deliver practical content without access to laboratories or equipment. We are developing further resources and welcome feedback to help us produce those you most need. Please email us or use the comment section below.
Practical videos | 14–16 students
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Practical videos: electrolysis