The electrolysis of some other solutions using inert electrodes
3 marks · EasyA student electrolyses aqueous sodium nitrate using inert electrodes. State the product formed at the cathode.
State the product formed at the anode.
Write a half-equation for the reaction at the cathode.
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(a) hydrogen
(b) oxygen
(c) 2H^+ + 2e^- → H_2
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Marking points
B1 (a) · 1 mark · States ‘hydrogen’ as the product at the cathode.
B1 (b) · 1 mark · States ‘oxygen’ as the product at the anode.
B1 (c) · 1 mark · Gives correct cathode half-equation: 2H⁺ + 2e⁻ → H₂.
Worked solution
a) At the cathode, hydrogen is formed because sodium is more reactive than hydrogen.
b) At the anode, oxygen is formed from the discharge of hydroxide ions (from water) because nitrate ions are not discharged.