State why the anode of an electrolytic cell is positive even though oxidation (loss of electrons) occurs there.
Answer
Because the external power source pulls electrons away from the anode, the anode is connected to the positive terminal and therefore has a positive potential.
Step-by-step solution
- Recall that in an electrolytic cell an external source forces the non‑spontaneous reaction.
- The source drives electrons from the positive terminal into the cathode and pulls electrons from the anode toward the negative terminal.
- Thus electrons leave the anode; to pull electrons away the anode must be at a higher (positive) potential than the cathode.
- Consequently the anode is connected to the positive pole of the power supply and is labelled positive.
- Oxidation still occurs at the anode because electrons are removed from the species there.
Common mistake: Confusing the sign of the anode in galvanic and electrolytic cells
Concept tested: Electrode polarity in electrolytic cells
Published · How this solution was prepared and checked
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