(HT only) Write half equations for reactions at the cathode in electrolysis.

In the subtopic Representation of reactions at electrodes as half equations (HT only), this learning objective focuses on (HT only) Write half equations for reactions at the cathode in electrolysis. It sits within Electrolysis for AQA GCSE Chemistry 8462 Unit 4.4, so the explanation must stay anchored to chemical changes rather than drifting into a general chemistry idea. Approved keywords to use include HT only, half equation, cathode, ion. Half equation. means a representation of a chemical reaction that shows either the reduction or oxidation process occurring at an electrode Avoid the mistake of students often confuse the direction of electron flow and incorrectly write half equations for the cathode, sometimes placing electrons on the wrong side; instead, remember that reduction occurs at the cathode, meaning positive ions gain electrons. Always place electrons on the left side of the equation when writing half equations for the cathode For exam answers, practice writing half equations for reactions at the cathode, focusing on the gain of electrons by positive ions Keep acid, alkali and base distinct; keep oxidation and reduction distinct; do not mix reduction with displacement; keep electrolysis separate from electroplating; distinguish anode from cathode, positive ions from negative ions, oxidation state from ionic charge, and strong acid from concentrated acid.