The electrolysis of other molten substances
2 marks · EasyExplain why sodium, and not chlorine, is formed at the cathode during the electrolysis of molten sodium chloride.
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Also accept: Candidates may mention only sodium ions are positive and migrate to cathode
Common mistakes: States sodium forms because it's a metal without mentioning ions
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Marking points
M1 · 1 mark · Explains that sodium ions (Na^+) are attracted to the cathode (negative electrode).
A1 · 1 mark · States that sodium ions gain electrons (are reduced) to form sodium metal at the cathode.
Worked solution
Sodium ions (Na^+) move towards the negative cathode and gain electrons to form sodium metal (reduction). Chlorine ions (Cl^-) are attracted to the positive anode instead.