Electrolysis

📌 The Big Idea

Electrolysis is a process where an electric current breaks down an ionic compound by forcing ion movement and electron transfer at the electrodes.

To understand electrolysis, you need to answer three questions:

• Why do ions move? (Because they're attracted to oppositely charged electrodes)
• What gets discharged? (The ion that's more easily oxidised or reduced)
• Where does it happen? (Cathode = reduction; Anode = oxidation)

📋 Chapter Overview

What is Electrolysis?

Electrolysis is the process in which a molten ionic compound is broken down by an electric current.

The same process also occurs in aqueous (dissolved) ionic solutions. But covalent compounds and solid ionic compounds cannot undergo electrolysis.

Why can't solids conduct electricity?

In an ionic compound in the solid state, the ions are fixed in fixed positions in the crystal lattice. They cannot move — and if they can't move, they can't carry charge through the circuit. Electrolysis needs mobile charge carriers.

But when you melt the compound or dissolve it in water, the ions are free to move around. That's when they can carry the electric current, and electrolysis becomes possible.

Key Vocabulary

The Basic Setup of an Electrolytic Cell