Question

Why is it necessary to use a new salt bridge for each electrochemical cell?

Answer 1

Because after one use some of the ions remains in the salt bridge. Now if you again use the same bridge the remaining ions will interpret in the reaction.

Answer 2

Explanation:

A salt bridge balances the charge when electrons move from one half cell to another half cell. During this process the salt bridge uses its electrolyte solution which further helps in balancing charges in both the half cells.

Moreover, as the ions are passing through the salt bridge so there is probability that few ions remain attached inside the salt bridge. If this salt bridge is used in another electrochemical cell then the attached ions will interrupt the reaction.

Therefore, for each electrochemical cell a new salt bridge is used.