Explain why the anode of an electrolytic cell is labelled positive even though oxidation (loss of electrons) occurs there.
Answer
The external power source pulls electrons away from the anode, so the anode is connected to the positive terminal of the source; therefore it is positive although oxidation takes place there.
Step-by-step solution
- In an electrolytic cell an external emf forces the non‑spontaneous reaction.
- The positive terminal of the source is connected to the electrode where electrons are removed.
- Removal of electrons means oxidation occurs at that electrode, which is therefore the anode.
- Because the source maintains a higher electric potential at this electrode, it is labelled positive despite being the site of oxidation.
Common mistake: Thinking the anode must be negative because oxidation occurs there
Concept tested: Electrode sign in electrolytic cell
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