Electrolysis
Overview
Strip away the wrapper of an aluminium can or look at the shine on a chrome-plated tap, and you are seeing the results of electrolysis. This process uses electricity to break down ionic compounds into their elements, powering industries from metal refining to water purification.
In this lesson you will discover why ionic substances only conduct when molten or dissolved, trace the movement of anions and cations to their electrodes, write half-equations for the reactions that happen there, and predict the products of several key electrolysis experiments that appear regularly on the Edexcel papers.
Objectives
- understand why covalent compounds do not conduct electricity
- understand why ionic compounds conduct electricity only when molten or in aqueous solution
- know that anion and cation are terms used to refer to negative and positive ions respectively
- describe experiments to investigate electrolysis, using inert electrodes, of molten compounds (including lead(II) bromide) and aqueous solutions (including sodium chloride, dilute sulfuric acid and copper(II) sulfate) and to predict the products
- write ionic half-equations representing the reactions at the electrodes during electrolysis and understand why these reactions are classified as oxidation or reduction
- practical: investigate the electrolysis of aqueous solutions
Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Electrolysis. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- Which of the following substances can conduct electricity? A) Solid sodium chloride B) Molten sodium chloride C) Solid sugar D) Liquid wax Answer: B
- During electrolysis, positive ions migrate toward the: A) Anode B) Cathode C) Electrolyte D) Power supply Answer: B
- What is produced at the cathode during the electrolysis of aqueous copper(II) sulfate? A) Oxygen B) Hydrogen C) Copper D) Sulfur Answer: C
- In the electrolysis of dilute sulfuric acid, what gas is produced at the anode? A) Hydrogen B) Oxygen C) Chlorine D) Sulfur dioxide Answer: B
- At which electrode does oxidation occur during electrolysis? A) Cathode B) Anode C) Both electrodes D) Neither electrode Answer: B
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
Recommended Books
Practice Mock Questions
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