Electrode potential and its applications

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it helps to understand electrode potential and explores the ways to use it in peaceful purposes :)

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Electrode potential and its applications

  1. 1. Prepared by Saba Shahzadi Course Coordinator Dr. Shahnaz Rashid
  2. 2. Topics to be learned….  Electrode Potential (definition)  Introduction to Electrochemistry  Electrochemical cells  Electrodes  Electrode potential  Concept of electrode potential  Half cell reactions  Types of electrode potentials  Cell Potential or E.M.F and its difference from Potential Difference  Dependence of Electrode Potential  Measurement of Electrode Potential  Electrochemical Series  Applications of Electrode Potential
  3. 3. Electrode Potential  Electrode potential is the voltage that an electrode is at , this has to measured versus a reference electrode.  Electrode potential is electromotive force of a cell that has two electrodes.
  4. 4. Introduction to Electrochemistry Electrochemistry is a branch of chemistry which involves the interconversion of electrical and chemical energy.  These conversions are carried out through electrochemical cells.
  5. 5. Electrochemical Cells There are two main types of electrochemical cells  Voltaic or Galvanic Cell  Electrolytic Cell The concept of electrode potentials could be understand by the composition of any one of the above.
  6. 6. Construction of Electrochemical cell
  7. 7. What are Electrodes?  Electrodes are the means by which liquid and living organisms are included in electrical circuits.  There are two electrodes in each electrochemical cell.  It may be a metal or a solid substance (mixture)  Its characteristics depend on the metal or solid and the solution in which it is dipped.
  8. 8. Electrode Potential  The electrical potential difference set up between the metal and its solution is known as electrode potential.
  9. 9. Half Cell Reactions  Both of the half cells have their own individual electrode potential because two different type of reaction take place on them.  At anode oxidation reaction occurs. At cathode reduction reaction occurs. Zn+2 + 2e- Zn
  10. 10. Concept of Electrode Potential Double layer Formation: The deposition of negative charges on the electrode when the chemical potential of copper’s ions in the metal is less than the chemical potential of the copper ions in solution then at the dipping of electrodes some quantity of the copper ions are hydrated and transferred to the metal which forms a positive charge on metal surface. These processes cause the double electrical layer.
  11. 11. Double Layer 1- metal 2 - solution
  12. 12. Types of electrode potential  Oxidation Potential  Reduction potential  Standard cell potential (standard hydrogen electrode)  Cell potential
  13. 13. Cell Potential and its difference from potential difference The difference between the electrode potentials of the two electrodes constituting an electrochemical cell is known as electromotive force (e.m.f.) or cell potential of a cell.
  14. 14. Dependence of Electrode Potential  Concentration  Temperature  Pressure (in case of gases only)
  15. 15. Measurement of Electrode potential  Electrode potential can never b measured directly it can only be measured by Comparing an electrode with a standard or reference electrode. These electrodes may be S.H.E or calomel electrode.
  16. 16. Electrochemical series
  17. 17. Applications of electrode Potential Determination of  Relative strengths of oxidizing and reducing agents.  Thermodynamic cell potential  Unknown concentration  pH  Free energy  Equilibrium constant  Solubility products  Dissociation constant  Titration curve
  18. 18. Continued… Predict the  Direction of electron flow  Feasibility of the reaction  Weather a metal can liberate hydrogen from acid or not

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