Passing electricity through compounds: electrolysis
3 marks · NormalA student investigates electrolysis using an aqueous solution of potassium iodide () and two inert electrodes.
State the name given to the compound in solution that conducts electricity in this experiment.
Name (i) the positive electrode, and (ii) the negative electrode.
During the experiment, which direction do the cations move in the electrolyte?
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) Electrolyte · must show 'electrolyte'
(b) (i) anode, (ii) cathode · must show anode, cathode
(c) Cations move towards the cathode (negative electrode). · must show towards cathode
Common mistakes: Confusing direction of cation movement; misnaming electrodes.
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Marking points
B1 (a) · 1 mark · States that the solution is called an electrolyte.
B1 (b) · 1 mark · Correctly names (i) the positive electrode as the anode and (ii) the negative electrode as the cathode.
B1 (c) · 1 mark · States that cations move towards the cathode (negative electrode).
Worked solution
a. The compound in solution that conducts electricity is called the electrolyte.
b. (i) The positive electrode is the anode; (ii) the negative electrode is the cathode.
c. Cations move towards the cathode (negative electrode) during electrolysis.