Electrolysis Process
Chemistry: AQA GCSE Higher, topic 4.4.1
Electrolysis
Electrolysis is the process that splits ionic compounds into the different elements that they are made of. Electrolysis happens using a solution that conducts electricity.
Electrolyte
- When ionic compounds are melted or dissolved in water, the ions (charged particles that have gained/lost electrons) are free to move around, and the liquid/solution will conduct electricity.
- Ionic compounds that dissolve in water to make a solution that conducts electricity are called electrolytes.
Electrodes
- When a voltage (direct current) is applied across an electrolyte, the charged ions are attracted to the electrode with the opposite charge to the ion.
- Positively charged ions are attracted to the negative electrode (cathode).
- Negatively charged ions are attracted to the positive electrode (anode).
Elements
- When an ion touches an electrode, electrons can be transferred, producing elements.
- E.g. If copper ions (Cu2+) are in a solution and a voltage is applied, they'll move to the cathode (negative electrode). When they touch the cathode, each Cu2+ ion will gain 2 electrons and form a copper metal.
Test yourself on Electrolysis Process
What happens when ionic compounds are dissolved in water?
A positively charged ion moves towards the cathode during electrolysis, following the same pattern as copper ions (Cu2+). What is likely to happen when this ion reaches the cathode?
A solid ionic compound has not been melted or dissolved in water. Why can this solid not act as an electrolyte?
How does an electrode differ from an electrolyte during electrolysis?
Why must an ionic compound be melted or dissolved in water before it can be used in electrolysis?