Chemistry in batteries. sandeep


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Chemistry in batteries. sandeep

  1. 1. Physical chemistry Sandeep O. kharwar
  2. 2. A lot happens inside a battery when you pop it into your flashlight , remote control or other wire free device. They produce electricity differ from battery to battery. Battery produce electricity due to electromagnetic reaction between anode, cathode and electrolyte while anode experiences an oxidation and cathode experiences reduction reaction. Modern batteries use variety of chemical to power their reaction.
  3. 3. 1) Zinc-carbon battery:-In this anode is zinc and cathode is manganese dioxide and electrolyte is ammonium chloride or zinc chloride. 2) Alkaline battery: It gets its name from the potassium hydroxide electrolyte ,which is an alkaline substance. 3) Lithium-ions battery (rechargeable): This is used in cell phones , digital cameras and even electric cars. 4) Lead-acid battery : This is the chemistry used in typical car battery .
  4. 4. Chemistry of Battery :Chemistry is the driving force behind the magic of battery. A battery is package of one or more galvanic cells used for the production and storage of electric energy by chemical means. A galvanic cell consist of at least two half cells, a reduction cell and an oxidation . A galvanic cell is also called a voltaic cell. The spontaneous reaction in it provide the electric or current . Two half cells can be together to form an electrolytic cell, which is used for electrolysis used to force no spontaneous chemical reaction
  5. 5. Oxidation reduction reaction: Many definition can be given to oxidation and reduction reaction. in term of electrochemistry, loss of electron is oxidation and gain of electrons is reduction. Oxidation and reduction cannot be carried out separately , they have to appear together in a chemical reaction. Thus the reaction called “Redox Reaction”. In redox reaction Reducting and Oxidizing agent form redox couple as they undergo the reaction: * oxidant +ne-  reductant e.g Cu(+2) + 2e- = Cu * reductant oxidant +ne-. E.g Zn = Zn(+2) + 2e-
  6. 6. element or compound ,but of different oxidation state. Example : Copper –zinc voltaic cells-
  7. 7. When a stick of zinc is inserted in a salt solution, there is tendency for Zn to lose electron according to the reaction , “ Zn=Zn(2+) +2e- ” This arrangement of a Zn electrode in solution containing Zn(2+) ions is a half cell, which represented as “ Zn/Zn(2+) ” In this zinc metal and Zn(2+) ions form a redox couple Zn(2+) being the oxidant and Zn the reductant
  8. 8. Similarly , when a stick of copper is inserted in a copper salt solution there is tendency for “Cu” to lose electron according to reaction “ Cu = Cu(2+) + 2e- “ redox couple represented as “Cu/Cu(2+)” However tendency of Zn to lose electron is stronger than that of Cu , when two cells are connected by salt bridge to form a closed circuit for electron so that copper actually gain electron to become copper metal and redox reaction represented as “ Cu(2+) + 2e- = Cu ” this arrangement is called galvanic cell , this battery represented as “Zn/Zn(2+)//Cu(2+)/Cu” in which two vertical line represent a salt bridge and single line represent the boundary between the two phase .
  9. 9. THANK YOU