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Electrochemistry VI
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Standard electrode potential

Shaillee Kaushal is teaching live on Unacademy Plus

Shaillee Kaushal
Faculty in Chemistry with a teaching experience of 14 years. Specialised in teaching for boards and competitions.

Unacademy user
Sir Diff between Vote of credit & Exceptional grant... एकहीसे काम नही चलता क्या?
Jab vote of credit se bhi kam na chale us situation me exceptional grant use ki jaegi.. aj tak aisa chance nai aya
Pradeep Phatak
3 years ago
  1. XII- 03 Electrochemistry -VI

  2. Electrode potential When a metal is placed in a solution of its ions, the metal acquires either a positive or a negative charge with respect to the solution Due to this a definite potential difference is developed between the metal and the solution. This potential difference is called electrode potential

  3. Reference elctrode: it is not possible to measure the absolute value ofa single electrode potential directly. On the difference in potential between two electrodes can be measured experimentally > For this purpose reference electrode is used. The e.m.f of the resultant cell is measured experimentally Ecell EAnode + Ecathode - Oxidation potential +Reduction potential. > Knowing the value of reference electrode, the value of other electrode can be determined.

  4. at 1 atm) > The hydrogen elctrode can act as a cathode or anode with respect to other elctrode. H30+ (aq.) If cathode: If anode 2H+ + 2e- H2

  5. Determination of standard electrode potential of Zn/Zn2+ electrode A zinc rod is dipped in 1M ZnSO, solution. This half cell is combined with a standard hydrogen electrode through a salt bridge. The cell can be representedby: Voltmeter ! cathode Zn rod (Anode) Zn(s)Izn2+ (aq)112n+(aq)|H2(g) Salt bridge H2 (at 1 atm) Oxidation Reduction The e.m.fof the cell is recorded 0.76 V cell : Anode + cathode 0.76Eode 0 So Eanode0.76 1M ZnSO4 1M HCI As oxidation takes place at the anode the reduction potential of Zn i.e n2+1Zn-0.76V

  6. (ii) Determination of standard elctrode poten tial Cu2+ /Cu electrode Valve voltmeter The cell can be representedas Electron flow if metal M has a nogative electrode 21 (aq) potential Electron flow if metal M has a positive electrode potential The e.m.fof the cell is recorded 0.34V Salt bridge E cell Eo anode + E cathode 0.34 0 + E cathode Ecu?+/Cu-0.34% Hydrogen Metal M Molar M Molar Ht