What is the function of a salt bridge in a galvanic cell ?

What is the function of a salt bridge in a galvanic cell ?

Ans.

In a galvanic cell, the salt bridge serves several important functions:

1. Maintaining electrical neutrality: During the operation of the galvanic cell, electrons flow from the anode to the cathode through the external circuit, causing a buildup of positive charge at the anode and a buildup of negative charge at the cathode. The salt bridge allows the migration of ions between the two half-cells, preventing the development of a large potential difference and maintaining electrical neutrality in each half-cell.

2. Completing the circuit: The salt bridge completes the electrical circuit by allowing the flow of ions between the two half-cells. Without the salt bridge, charge buildup would occur in each half-cell, and the flow of electrons through the external circuit would cease.

3. Preventing mixing of solutions: The salt bridge consists of an inert electrolyte, such as potassium chloride (KCl) or sodium nitrate (NaNO3), which is not involved in the electrochemical reactions occurring in the cell. This prevents the solutions in the two half-cells from mixing while still allowing ion migration.

4. Maintaining equilibrium: The salt bridge helps maintain the electrochemical equilibrium within the cell. It allows ions to move into and out of the half-cells, ensuring that the concentrations of reactants and products remain constant and the cell operates under optimal conditions.

Overall, the salt bridge plays a crucial role in the proper functioning of a galvanic cell by maintaining electrical neutrality, completing the circuit, preventing solution mixing, and maintaining equilibrium.