Loading please wait

The smart way to improve grades

Comprehensive & curriculum aligned

Try an activity or get started for free

Understand Electrolysis

Worksheet Overview

 

An electric current can be used to separate compounds into their different elements, and also to create new products using a method called electrolysis. The diagram below shows an electrolytic cell while electrolysis of sodium chloride (NaCl) is taking place:

 

Image of electrolysis

 

The principle is that the electric current separates the compound into its ions. Ions are atoms that have gained or lost one or more electrons in order to make the compound with the other element(s). The electrodes used for electrolysis are a positive one (anode), which attracts negative ions (anions), and a negative one (cathode), which attracts positive ions (cations). 

The electrolyte is the molten compound or the solution that is separated during electrolysis, and it must be able to conduct electricity.

 

Electrolysis of dilute sulfuric acid

Hydrogen is made at the cathode2H+ + 2e- Right facing arrow H2. The positive hydrogen ions migrate towards the negative cathode, gain one electron each and are discharged as hydrogen gas.

Oxygen is made at the anode: 4OH- - 4e-  Right pointing arrow 2H2O + O2. The negative hydroxyl ions migrate towards the positive anode, they lose one electron each and combine to form water and oxygen.

 

Purifying copper

Electrolysis is also used to purify metals, such as copper. Copper is extracted as an ore (compounds of copper with other elements) and is purified with this method. The anode is the impure copper;  it dissolves into the electrolyte, and pure copper coats the cathode. This is called electroplating.

 

Let's have a go at some questions now.

What is EdPlace?

We're your National Curriculum aligned online education content provider helping each child succeed in English, maths and science from year 1 to GCSE. With an EdPlace account you’ll be able to track and measure progress, helping each child achieve their best. We build confidence and attainment by personalising each child’s learning at a level that suits them.

Get started
laptop

Try an activity or get started for free

  • educational
  • bettfutures
  • cxa
  • pta
  • era2016
  • BDA award
  • Explore LearningTuition Partner
  • tacm