## Salt Brldge and Its Eunctions Chemistry Notes

Salt Bridge and Its Functions :

→ It is a U-tube filled with concentrated solution of inert electrolyte like KNO, NH, Cl, KCl etc., which is kept inverted. Here, for electrolytes :

• The movement of cation and anion should be nearly same.
• Ions should not be chemically reactive with ions of cell.
• Ions should not be included in chemical change.

→ Functions of salt Bridge

• Electric circuit is completed by salt bridge.
• Salt bridge mantains electrical neutrality of solutions of both half-cells.

→ As we know that when circuit is completed then electrons are transferred from anode to cathode as a result, positive charge is accumulated near anode and negative charge is accumulated near cathode. In above cell, the concentration of Zn2+ ions increases near anode and concentration of so ions increases near cathode.

→ Due to this reason, the flow of electron from anode and its receiving at cathode will be stopped. $$\mathrm{SO}_{4}^{2-}$$ reaction will stop and flow of electric current will stop. In such condition, the anions of electrolyte present in salt bridge move at anode and cations move at cathode and maintain electric neutrality. Inert electrolyte present in salt bridge prevents accumulation of charges near electrodes. Porous pot may also be used in device in place of salt bridge.