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DIFFERENT TYPES OF CELLS. CELL CELL IS A DEVICE WHICH CONVERT CHEMICAL ENERGY INTO ELECTRICAL ENERGY AND VICE VERSA. TYPES OF CELLS ELECTROCHEMICAL CELL :A DEVICE WHICH CONVERT CHEMICAL ENERGY INTO ELECTRICAL ENEGRY eg DRY CELL, ,ZINC CADMIUM CELL & FUEL CELL
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DIFFERENT TYPES OF CELLS
CELL CELL IS A DEVICE WHICH CONVERT CHEMICAL ENERGY INTO ELECTRICAL ENERGY AND VICE VERSA
TYPES OF CELLS ELECTROCHEMICAL CELL:A DEVICE WHICH CONVERT CHEMICAL ENERGY INTO ELECTRICAL ENEGRY eg DRY CELL, ,ZINC CADMIUM CELL & FUEL CELL ELECTROLYTIC CELL:-A DEVICE WHICH CONVER ELECTRICAL ENERGY INTO CHEMICAL ENERGY egDOWNS CELL, CASTNER-KELLNER CELL
– + – + – + The electrolytic cell • Electric current forces charges on electrodes Na+ Na+ Cl– Cl– • Na+ is attracted to negative, Cl– to positive • Na+ takes up an electron: Na+(aq) + e– Na • Cl– gives up an electron: 2Cl–(aq) Cl2 + 2e– • Thus electricity continues to flow • Pure Na is deposited, Cl2 gas is produced
Dry cell At anode zn-------------------zn2++2e- At cathode 2 MnO2+2NH4++2e---Mn2O3 +H2O+2NH3( ) NH3 IS CONSUMED IN COMPLEX FORMATION WITH Zn 2+ ION Zn2++4NH3 ---------------- [Zn(NH3)4}2+ -----------[Zn(NH3)4]Cl2 At anode Zn-------------------Zn2++2e- At cathode 2 MnO2+2NH4++2e---Mn2O3 +H2O+2NH3( ) NH3 IS CONSUMED IN COMPLEX FORMATION WITH Zn 2+ ION Zn2++4NH3 --- [Zn(NH3)4}2+ --------2Cl------[Zn(NH3)4]Cl2
Fuel cell Cathode: O2(g) + 2H2O(l ) + 4e–⎯→ 4OH–(aq) Anode: 2H2 (g) + 4OH–(aq) ⎯→ 4H2O(l) + 4e– OVERALL REACTION 2H2(g) + O2(g) ⎯→ 2 H2O(l )
MERITS OF FUEL CELL ECO FRIENDLY CONTINUOUS SOURSE OF ENERGY HIGH EFFICIENCY DEMERITS OF FUEL CELL VERY EXPENSIVE HEAVY NOT CONVENIENT TO USE HIGHLY CORROSIVE NATURE OF THE ELECTROLYTE