NJC 2026 Electrochemistry Part 2 (Student)

Electrolytic Cell (Part 2) Content • Electrolysis (i) factors affecting the amount of substance liberated during electrolysis (ii) the Faraday constant; the Avogadro constant; their relationship (iii) industrial uses of electrolysis Learning Outcomes Candidates should be able to: (l) state the relationship, F = Le, between the Faraday constant, the Avogadro constant and the charge on the electron (m) predict the identity of the substance liberated during electrolysis from the state of electrolyte (molten or aqueous), position in the redox series (electrode potential) and concentration (n) calculate: (i) the quantity of charge passed during electrolysis (ii) the mass and/or volume of substance liberated during electrolysis (o) explain, in terms of the electrode reactions, the industrial processes of: (i) the anodising of aluminium (ii) the electrolytic purification of copper [technical details are not required] References • Advanced Chemistry, by Michael Clugston and Rosalind Flemming. • Chemistry for Advanced Level, by Peter Cann and Peter Hughes • Chemistry, by Raymond Chang Copyright © National Junior College All Rights Reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording or any other information storage and retrieval system, without prior permission in writing from the copyright owner.

Comparison of Electrochemical (Part 1) and Electrolytic cell (Part 2) ELECTROCHEMICAL CELL ELECTROLYTIC CELL Energy change chemical energy → electrical energy electrical energy → chemical energy Cell Reaction Spontaneous Chemical reaction takes place to generate electric current within celll (battery). Non-spontaneous External electric current is applied to drive the reaction to occur. Cathode (reduction) Positive (+) electrode Negative (–) electrode Anode (oxidation) Negative (–) electrode Positive (+) electrode Note: 1. In both electrochemical and electrolytic cells, oxidation always takes place at the anode while reduction always takes place at the cathode. 2. Polarity of electrode always follow the polarity of the battery. [ElectroCHEMICAL cell] The two half-cells form the battery. Anode is the negative terminal of the battery that releases electrons while cathode is the positive terminal of the battery that accepts electrons. [ElectroLYTIC cell] The polarities of the electrode are reversed, as the electrodes follows the polarity of the battery terminal it is connected to. • anode (+ve) is connected to the +ve terminal of battery and attracts anions (−ve) • cathode (−ve) is connected to the −ve terminal of battery and attracts cations (+ve)

Pause and ponder Which half-reaction occurs in which electrode? Anode, Oxidation; Reduction, Cathode 1 The Electrolytic Cell Electrolysis is the process in whi