Department
Light Emitting Diode of Chemistry
Raghu
(LED) Engineering College
Electrochemistry and corrosion
Unit-II
1
, ELECTRO CHEMICAL CELL / GALVANIC CELLS /
VOLTAIC CELL:
• An electrochemical cell is a device which converts chemical energy into
electrical energy.
• The redox reaction is utilized for generation of electrical energy.
• The electrochemical cells are commonly referred as Voltaic or Galvanic
cells.
• The electromotive force (EMF) of such cell is directly proportional to
intensity of chemical reaction taking place in it.
• The electrochemical cell is divided into two half cells. The half-cell
electrode where oxidation (loss of electrons) occurs is called anode
(negative electrode). The half-cell electrode where reduction (gain of
electrons) occurs is called cathode (positive electrode).
• An electrochemical cell is the coupling of these two half cells.
2
, Daniel cell
• The Daniel cell is a typical example of Galvanic cell.
• Daniel cell consists of a beaker containing copper rod dipped in CuSO4 solution
which is connected to another beaker containing zinc rod dipped in ZnSO4
solution by a salt bridge.
• Salt bridge is an inverted U-tube containing saturated solution of some
electrolyte such as KCl, KNO3, NH4NO3 which does not undergo chemical change
during the process. The saturated solution is generally taken in agar-agar jelly or
gelatin.
• The salt bridge allows the flow of ions to pass through it when the flow of electric
current takes place. It completes the electrical circuit and maintains the electrical
neutrality of two half-cell solutions.
3
, 4
Light Emitting Diode of Chemistry
Raghu
(LED) Engineering College
Electrochemistry and corrosion
Unit-II
1
, ELECTRO CHEMICAL CELL / GALVANIC CELLS /
VOLTAIC CELL:
• An electrochemical cell is a device which converts chemical energy into
electrical energy.
• The redox reaction is utilized for generation of electrical energy.
• The electrochemical cells are commonly referred as Voltaic or Galvanic
cells.
• The electromotive force (EMF) of such cell is directly proportional to
intensity of chemical reaction taking place in it.
• The electrochemical cell is divided into two half cells. The half-cell
electrode where oxidation (loss of electrons) occurs is called anode
(negative electrode). The half-cell electrode where reduction (gain of
electrons) occurs is called cathode (positive electrode).
• An electrochemical cell is the coupling of these two half cells.
2
, Daniel cell
• The Daniel cell is a typical example of Galvanic cell.
• Daniel cell consists of a beaker containing copper rod dipped in CuSO4 solution
which is connected to another beaker containing zinc rod dipped in ZnSO4
solution by a salt bridge.
• Salt bridge is an inverted U-tube containing saturated solution of some
electrolyte such as KCl, KNO3, NH4NO3 which does not undergo chemical change
during the process. The saturated solution is generally taken in agar-agar jelly or
gelatin.
• The salt bridge allows the flow of ions to pass through it when the flow of electric
current takes place. It completes the electrical circuit and maintains the electrical
neutrality of two half-cell solutions.
3
, 4
