LECLANCHE CELL

LECLANCHE CELL:

* IT IS A PRIMARY CELL

* IT IS USED FOR SUPPLYING INTERMITTENT CURRENT

* ANODE - CARBON ELECTRODE ( PACKED IN A POROUS POT CONTAINING MnO2 + CHARCOAL POWDER )
   CATHODE - ZINC ROD
   ELECTROLYTE -NH4Cl ( IN WHICH ANODE & CATHODE ARE IMMERSED )
   EMF - 1.5 V

GEORGES LECLANCHE

                                                CURRENT - 0.25 A

*DUE TO OXIDATION REACTION ZINC REACTS WITH AMMONIUM CHLORIDE GIVING OUT Zn IONS AND 2 ELECTRONS i.e.,

*Zn + 2NH4Cl -----> 2 NH3 (GAS) + ZnCl2 + 2 H + 2 electrons

( OXIDATION REACTION TAKES PLACE AT THE CATHODE )

*AMMONIA GAS ESCAPES AND H2 IONS DIFFUSE THROUGH THE PORES OF POROUS POT AND REACT WITH MnO2.

*2 HYDROGEN IONS DISCHARGED AT THE ANODE.

*WHEN THE CELL IS CONNECTED BY A WIRE EXTERNALLY TWO ELECTRONS ON THE Zn ROD PASS THROUGH THE EXTERNAL CIRCUIT AND REACH THE CARBON ROD NEUTRALISING THE POSITIVE CHARGE.

*THUS CURRENT FLOW FROM CARBON TO ZINC.