Question

What substance in an electrochemical cell balances the charge imbalance that would otherwise result from the flow of electrons?

Answer 1

The salt bridge is the element which does the work of maintaining the charge balance in an electrochemical cell.

As the cell functions, electrons keep flowing from anode to cathode, which causes a buildup of positive ions in the oxidation half cell and a buildup of negative ions in the reduction half cell.

In order to maintain the neutrality of the two solutions, the salt bridge releases the corresponding ions into the two half cells to neutralize the extra charge build up.

Hope this helps !