Electrolysis

Part of the Oxidation and Reduction section of Coddy's Chemistry journey. Lesson 21 of 27.

Electrolysis drives a redox reaction with electricity. The liquid must have free ions.

Cathode (−): reduction, ions take electrons. Anode (+): oxidation, ions give electrons.

Molten NaCl:

Na⁺ + e⁻ → Na

2Cl⁻ → Cl₂ + 2e⁻

Challenge

In the Downs cell, molten sodium chloride is electrolyzed to make sodium metal and chlorine gas: NaCl → Na + Cl₂. Which element is oxidized, and which is reduced?

Try it yourself

Oxidation numbersFollow the electrons

NaClNaCl₂

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Oxidation and Reduction

1Electron Transfer

What Is Oxidation Oxidation Numbers Rules for Oxidation Numbers Oxidation Numbers in Ions Recap - Number Painter

4Metals and Reactivity

The Reactivity Series Displacement Reactions Metals and Acids Corrosion and Rust Recap - Metal Contest

2Redox Reactions

Spotting Redox Oxidizing Agents Reducing Agents Electrons Passed Recap - Who Gave Electrons

5Electrochemistry

ElectrolysisElectrolysis of Melts Cells and Batteries Recap - Smelter

3Half-Equations

Writing Half-Equations Balancing with Electrons Half-Equations in Acid Combining Half-Equations Recap - Permanganate

6Practice Problems

Recap - Bleach and Iodide Recap - Copper and Silver Recap - Bromine Redox