An inert electrode is an electrode such as carbon or platinum that does not take part in the electrode reaction; it only carries the current.
An inert electrode is an electrode, such as carbon (graphite) or platinum, that does not take part in the electrode reaction. It only carries the current to and from the electrolyte. Malay: elektrod lengai · Chinese: 惰性电极.
Because an inert electrode does not react, the products of electrolysis come entirely from the ions in the electrolyte. At the cathode a cation is reduced; at the anode an anion is oxidised; the electrode itself is unchanged in mass and identity. This makes inert electrodes the standard choice when you want to study the ions of the electrolyte on their own, which is why most electrolysis experiments in the syllabus use carbon electrodes.
Example. In the electrolysis of dilute sulfuric acid with carbon electrodes, hydrogen is released at the cathode and oxygen at the anode, while the carbon rods stay the same. The gases come from the water and the acid, not from the electrodes.
Confusion to avoid. Do not confuse an inert electrode with an active electrode. An active electrode, such as copper, takes part in the reaction and changes: the copper anode dissolves and copper is deposited on the cathode. If a question uses copper or silver electrodes, expect the anode to dissolve; if it uses carbon or platinum, expect a gas or a deposit that comes only from the electrolyte.
Why it matters for products. Choosing an inert or active electrode is one of the three factors that decide the anode product, so a question can change its answer simply by changing the electrode material. Always check which type is specified before predicting what forms.
A quick way to tell them apart. If a question gives carbon or platinum electrodes, treat them as inert and look only at the ions of the electrolyte; if it gives copper, silver or another reactive metal as the electrode, expect the anode to react. Naming the electrode material in your answer, and stating clearly whether it is inert, shows the examiner that you understand why the products are what they are, not just what they are.
Recognising an inert electrode, and stating that it does not react, is a common step in explaining electrolysis results in SPM Chemistry.
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