In an electrochemical cell, a redox reaction involves both oxidation and reduction happening at different electrodes. Here’s what happens:
1. At the Anode (Oxidation)
- The metal loses electrons.
- These electrons flow through an external wire toward the cathode.
- Example: Zinc in a Daniell cell gives electrons and becomes Zn²⁺.
2. At the Cathode (Reduction)
- Electrons coming from the anode combine with ions in the solution.
- The ions gain electrons and form neutral atoms or molecules.
- Example: Cu²⁺ ions in solution gain electrons and deposit as copper metal.
3. Overall Effect
- Electrons move from anode to cathode through the external circuit, producing electricity.
- Ions move through the electrolyte or salt bridge to maintain charge balance.
In short: In a redox reaction inside an electrochemical cell:
- Anode: metal loses electrons → oxidation
- Cathode: ions gain electrons → reduction
- Electrons flow through a wire → electric current is produced.