Question

The purpose of a salt bridge in a galvanic cell is to :

• A. Prevent accumulation of charges around the electrodes
• B. Facilitate continuity of the cell reaction
• C. To produce current at a constant strength
• D. Induce accumulation of charges around the electrodes

Answer 1

Answer: (A), (B), (C)

To produce current at a constant strength

Salt bridge is an U–shaped inverted tube that contains a
gel (paste of agar-agar powder) permeated with an inert electrolyte (eg: $KCl$). It connects two electrodes internally or connects the two solutions.

If electrodes are not connected internally, initially the cell generates electrical energy but after sometime, electrodes get polarised due to accumulation of opposite charged ions around the electrodes. Thus, the cell stops working or electron flow stops.
Hence, for continuous generation of electrical energy, the electrodes need to be internally connected by salt bridge.
The cations and anions of the electrolyte in salt bridge migrates toward cathode and anode and polarize some of the oppositely charged ions in the solution towards themselves. Thus, it prevent the accumulation of charge around electrodes and the cell keeps working.
Thus, statement (a), (b) and (c) are correct.