Question

Why is it necessary to use salt bridge in a galvanic cell ?

Hint:

Without a salt bridge, charge accumulation occurs in the half-cells and the galvanic cell stops functioning after a short time.

Answer 1

Concept: A galvanic cell generates electrical energy through spontaneous redox reactions occurring in two separate half-cells. As the reaction proceeds, charge imbalance develops in the two compartments.

Explanation: At the anode, oxidation produces excess positive ions. At the cathode, positive ions are consumed, leaving excess negative ions. This accumulation of charge would eventually stop the flow of electrons. A salt bridge prevents this problem by allowing migration of ions. Its functions are:

• Maintains electrical neutrality in both half-cells.

• Completes the electrical circuit.

• Prevents direct mixing of the two electrolytes.

• Minimizes liquid junction potential.
Thus continuous current can flow through the external circuit.

Final Answer \[ \boxed{ \text{A salt bridge maintains electrical neutrality and completes the circuit} \\ \text{by permitting the migration of ions between the two half-cells.} } \]