Electrolysis

To understand electrolysis, you need to know what an ionic substance is.

Ionic substances form when a metal reacts with a non-metal. They contain charged particles called ions [ions: Electrically charged particles, formed when an atom or molecule gains or loses electrons. ]. For example, sodium chloride forms when sodium reacts with chlorine. It contains positively charged sodium ions and negatively charged chloride ions. Ionic substances can be broken down by electricity.

For electrolysis to work, the ions must be free to move. Ions are free to move when an ionic substance is dissolved in water or molten [molten: Molten means reduced to liquid form by heating. It is mainly used to describe rock, glass or metal. ] (melted). For example, if electricity is passed through copper chloride solution, the copper chloride is broken down to form copper metal and chlorine gas.

Electrolysis

Here is what happens during electrolysis:

• Positively charged ions move to the negative electrode during electrolysis. They receive electrons and are reduced [reduction: Reduction is a reaction in which oxygen is removed from a substance. Reduction also means a gain in electrons. ].
• Negatively charged ions move to the positive electrode during electrolysis. They lose electrons and are oxidised [oxidation: Oxidation is a reaction in which oxygen combines with a substance. Oxidation also means a loss of electrons. ].