Electrolysis
Overview
Pass an electric current through a molten salt and something remarkable happens: the compound splits apart, with a metal appearing at one electrode and a non-metal at the other. This is electrolysis, the use of electricity to break down a compound that no simple chemical reaction could.
In this lesson you will learn what electrolysis is, the meaning of the key terms electrolyte, electrode, cathode and anode, and how a molten ionic compound is decomposed. Molten lead(II) bromide is the worked example.
Objectives
- Define electrolysis as the decomposition of an ionic compound, when molten or in aqueous solution, by the passage of an electric current.
- Identify in simple electrolytic cells: (a) the anode as the positive electrode (b) the cathode as the negative electrode (c) the electrolyte as the molten or aqueous substance that undergoes electrolysis.
- [Supplement] Describe the transfer of charge during electrolysis to include: (a) the movement of electrons in the external circuit (b) the loss or gain of electrons at the electrodes (c) the movement of ions in the electrolyte.
Audio Lesson
Listen to this lesson in the app
Mind map
This topic is mapped out so you can see how the ideas connect.
Open the mind map in the app
Flashcards
Quick recall practice on the facts this topic is tested on.
Practise these cards in the app
Lesson Note
Complete Note Available on the Green Bridge App
Get the Green Bridge CBT app on your phone or computer for the complete IGCSE library: past papers, mark schemes, mind maps, flashcards and audio lessons.
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.
- Electrolysis is the breakdown of an ionic compound by: A. Heating alone B. Passing an electric current through it C. Adding water D. Adding an acid Answer: B
- An electrolyte conducts electricity when it is: A. Solid B. Molten or dissolved C. Frozen D. Pure and dry Answer: B
- The cathode in an electrolysis cell is: A. Positive and attracts positive ions B. Negative and attracts positive ions C. Negative and attracts negative ions D. Positive and attracts negative ions Answer: B
- During the electrolysis of molten lead(II) bromide, the product at the cathode is: A. Bromine B. Lead C. Oxygen D. Hydrogen Answer: B
- Inert electrodes are often made of: A. Sodium B. Carbon or platinum C. Iron D. Lead Answer: B
Work through these questions in the app
Work through these questions in the app
Recommended Books
Practice Mock Questions
Want to practice mock questions on Electrolysis? Download the Green Bridge CBT app to access mock questions and full practice assessments for this topic.
Download The App On Google Playstore
Everything you need to excel in your exams
