A salt bridge is a component of an electrochemical cell that connects the two half-cells and allows ions to flow between them.
Its main purposes are:
- To maintain electrical neutrality in each half-cell by allowing positive and negative ions to move.
- To complete the circuit, enabling the flow of electrons through the external wire.
- To prevent the solutions in the two half-cells from mixing directly, which could stop the reaction.
In simple terms, a salt bridge is like a pathway for ions that keeps the cell working properly by balancing charges as electrons move from the anode to the cathode.
Commonly, it contains a gel or solution of a neutral salt such as potassium nitrate or potassium chloride.