Sodium chloride can be electrolysed when it is molten or when it is dissolved in water.
Molten sodium chloride is electrolysed using inert electrodes.
Name the product at each electrode.
Sodium chloride solution contains four different ions. Two of the ions come from sodium chloride. The other two ions come from water.
Name the two ions that come from water.
When sodium chloride solution is electrolysed, hydrogen is made at the cathode, not sodium.
Explain why.
Name the gas made at the anode when the sodium chloride solution is electrolysed.
Give a reason for your answer.
After electrolysis, the student adds universal indicator to the solution left in the beaker. The indicator turns purple.
Name the substance in the solution that causes this colour.
52 exam-style questions on OCR GCSE Chemistry 3.4 Electrolysis, covering 3.4.1 Products formed at the electrodes in electrolysis and 3.4.2 The technique of electrolysis. Each one has a worked solution and a mark scheme showing where the marks go.