Electrolysis happens when an electric current is passed through an ionic compound which has been melted or dissolved. Electrolysis has a wide range of uses including :
electroplating, extraction of aluminium, production of chlorine , purification of copper .
This page helps you to understand and explain the various changes that can happen in electrolysis.
A liquid substance containing ions which are mobile can conduct an electric current. When this happens chemical changes take place at the electrodes. Electrons are given off at the negative electrode ( cathode) and electrons are taken away from the positive electrode ( anode).
The ions ( which are mobile because they are molten or dissolved) will migrate as the electric field is applied. The positive ions will migrate to the negative electrode and the negative ions migrate to the positive electrode.
Melting Sodium Chloride
Q1. At what point does the salt start conducting? Open or Close
The salt begins to conduct an electric current once it has all become molten.
Q3. Why does the lamp go out again? Open or Close
The molten salt is allowed to cool and so it solidifies and stops being able to conduct
Q2. What changes can you see taking place in the sodium chloride whilst it it conducting? Open or Close
It looks like the salt is reacting and producing some gases