The difference between metallic and electrolytic conduction, strong and weak electrolytes, what happens at the anode and cathode, and how to predict the products of electrolysis of molten and aqueous compounds.
5 narrated scenes. Press play, listen and read along — the points appear as they are explained. Use ‹ Prev / Next › or the scene bar to jump to any scene.
Electrolysis is how we make chlorine, aluminium and sodium hydroxide, how we plate a bracelet with silver and how we purify copper. The rules for predicting what appears at each electrode are the same every time.
Narration uses your device’s built-in voice. No sound? Switch to “Captions only” — the captions advance on their own.
Copy these into your notebook in your own words — that is how they stick.
Mobile electrons; no chemical change.
Mobile ions (molten or aqueous); chemical change.
Decomposition of an ionic compound by an electric current.
Anions lose electrons: oxidation.
Cations gain electrons: reduction.
Less reactive of H⁺ and the metal ion: Cu, Ag deposited; Na, K, Ca, Mg, Al, Zn → H₂.
Conc. halide → halogen; otherwise OH⁻ → O₂.
Anode dissolves; cathode plated; blue colour unchanged.
3 quick games on this lesson. Earn XP and badges as you play — your best score for each game is saved. Games are for practice and do not change your exam readiness. More games in the Chemistry Arcade.
8 items modelled on real CSEC Paper 1 questions. Choose one answer for each, then check. Aim for 80% or better. Work each item on paper first.
Write full answers, then reveal the mark scheme and tick the points you earned (15 marks in total). Show all your working — method marks count. Your answers are saved on this device.
Question 1 [15 marks]
Concentrated aqueous sodium chloride is electrolysed using graphite electrodes.
(a) (a) Define electrolysis. [2]
(b) (b) List all the ions present in the solution. [2]
(c) (c) Name the product at each electrode and write a half-equation. [4]
(d) (d) Explain why hydrogen, not sodium, is produced at the cathode. [2]
(e) (e) Name the substance left in the solution and state a test using litmus. [2]
(f) (f) State what happens to the mass of each electrode when copper(II) sulfate solution is electrolysed with copper electrodes. [3]
Find these in your own past-paper booklets for extra timed practice. Items above are written in the style of these papers; any adapted from a specific question say so.