A galvanic cell (also called a voltaic cell) is a device that converts chemical energy into electrical energy through a spontaneous redox reaction. Unlike an electrolytic cell (which needs electricity), a galvanic cell produces electricity on its own.
Parts of a galvanic cell:
- Two Half-Cells – Each contains a metal electrode dipped in a solution of its ions.
- Anode (–): Electrode where oxidation occurs (electrons are released).
- Cathode (+): Electrode where reduction occurs (electrons are gained).
- External Circuit – Connects the two electrodes, allowing electrons to flow from anode to cathode.
- Salt Bridge – A tube filled with an electrolyte that maintains electrical neutrality by allowing ion movement.
How it works:
- The spontaneous chemical reaction pushes electrons from the anode → cathode through the external wire.
- This electron flow generates an electric current.
Example: Daniell Cell
- Anode (Zn electrode): Zn → Zn²⁺ + 2e⁻ (oxidation)
- Cathode (Cu electrode): Cu²⁺ + 2e⁻ → Cu (reduction)
- Result: The cell produces electricity as zinc dissolves and copper is deposited.
In simple words: A galvanic cell is like a chemical battery that generates electricity naturally from a chemical reaction.