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Key Questions:

1. Why is hydrogen produced instead of sodium in the electrolysis of NaCl solution?
   • The ions discharged when an aqueous solution is electrolysed using inert electrodes depend on the relative reactivity of the elements involved. Sodium is more reactive than hydrogen so forms NaOH in solution. Hydrogen gas is discharged at the electrode.
2. When is hydrogen produced at the negative electrode in electrolysis?
   • At the negative electrode (cathode), hydrogen is produced if the metal is more reactive than hydrogen.
3. When is oxygen not produced at the positive electrode?
   • At the positive electrode (anode), oxygen is produced unless the solution contains halide ions when the halogen is produced.
4. Why are hydrogen and oxygen often discharged in the electrolysis of aqueous ionic solutions?
   • Oxygen and hydrogen gas are discharged because in the aqueous solution water molecules break down producing hydrogen ions and hydroxide ions that are discharged.
5. What are the three products made in the electrolysis of aqueous sodium chloride?
   • The three products of the electrolysis of NaCl would be NaOH, Cl2 and H2.
6. (HT)
   • (HT)