All Activities
Science

Electrochemistry

Overview

Students investigate how electricity drives chemical reactions and how chemical reactions can generate electricity, discovering the principles of electrochemistry.

Learning Objective
Students understand electrolysis and the principles of electrochemical cells, connecting these to industrial applications and the concept of redox reactions.

Resources needed

  • Salt water solution
  • Two carbon electrodes (pencil graphite works)
  • One battery
  • Connecting wire

Lesson stages

0 / 7 done
  1. 1 Introduce electrolysis: using electricity to decompose an ionic compound.
  2. 2 Set up the apparatus: electrodes in salt water solution connected to a battery.
  3. 3 Observe: bubbles form at both electrodes. Test with a glowing splint (oxygen) and burning splint (hydrogen).
  4. 4 Explain: at the cathode (negative), positive ions (H+) gain electrons and become hydrogen gas. At the anode (positive), negative ions (Cl-) lose electrons and become chlorine gas.
  5. 5 Introduce the concept of oxidation and reduction: oxidation = loss of electrons, reduction = gain of electrons (OIL RIG).
  6. 6 Introduce electrochemical cells: a spontaneous redox reaction generates electricity. The classic example: zinc and copper in salt solution.
  7. 7 Give industrial applications: electroplating, extraction of aluminium from aluminium oxide, chlorine production for water treatment.

Tap a step to mark it as done.

Variations

  • Electroplate an object using copper sulfate solution and copper electrodes.
  • Measure the voltage produced by different metal combinations as galvanic cells.
  • Discuss the chlor-alkali industry: large-scale electrolysis of brine to produce chlorine, hydrogen, and sodium hydroxide.
More information

Teach: electrolysis, electrode, cathode, anode, oxidation, reduction, redox, OIL RIG, galvanic cell, electroplating. The OIL RIG mnemonic — Oxidation Is Loss, Reduction Is Gain (of electrons) — is the most useful memory tool in this topic.

Focus on the electrolysis setup and observations before introducing the oxidation/reduction explanation at the particle level.

Can students describe what happens at the cathode and anode during electrolysis? Can they use OIL RIG correctly to identify oxidation and reduction in a given reaction?

Pencil graphite as electrodes, salt water as electrolyte, and a battery is all that is needed. The electrolysis of salt water is safe and produces visible results. All other equipment is improvised.

Students often think electrolysis only works with water. Any ionic compound in solution or in molten form can be electrolysed — the key requirement is mobile ions, not water.

Electrochemistry underpins battery technology, metal extraction, electroplating, and fuel cell development. Understanding it connects chemistry to energy technology and sustainability.

Activity details
Secondary Challenging 30 minutes 10 minutes prep Small Group Indoor & Outdoor
Topics
Electrochemistry Electrolysis Redox