Electrolysis of molten salts
I can explain why salts can be electrolysed when in their liquid state, and describe the reactions taking place.
Electrolysis of molten salts
I can explain why salts can be electrolysed when in their liquid state, and describe the reactions taking place.
Lesson details
Key learning points
- A solid ionic compound cannot conduct electricity.
- Salts are ionic compounds which can be electrolysed when they are in the molten state.
- Gases may be formed at the electrodes.
- Freely moving ions can reach the electrodes and undergo oxidation or reduction.
- A non-metal always forms at the positive electrode, and a metal forms at the negative electrode.
Common misconception
Students often think that during electrolysis the charge carriers are electrons and not ions.
Revisit the structure of ionic compounds in the solid and liquid states. Point out that there are no delocalised electrons. The electrons are associated with ions and so are unable to move through the electrolyte. Ions can move in the liquid state.
Keywords
Molten - the term used to describe a liquid substance formed by heating ionic compounds and metal ores.
Anode - A positively charged electrode, in an electrolysis cell, to which the anions are attracted.
Cathode - A negatively charged electrode, in an electrolysis cell, to which the cations are attracted.
Anion - A negatively charged ion
Cation - A positively charged ion
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Video
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