standard electrode potential of cupper and zinc

Determination of the standard electrode potential of copper and zinc

The standard electrode potential of copper and zinc is an important experiment around the world. For general chemistry as well as applied chemistry, this experiment is useful. With reference to a standard hydrogen electrode (SHE), values for standard electrode potentials are most often tabulated at 25 ° C. It is also an electron exchange reaction that means Redox reaction.

Determination of the standard electrode potential of copper and zinc:

To determine the standard electrode potential of copper and zinc the standard calomel electrode (SCE) is connected with copper or zinc electrode and the emf of the cell is determined by means of a potentiometer, Thus-

Ecell = Ecathode(red) – Eanode(red)

The zinc cell (Zn) could be portrayed as-

Zn/Zn2+ || Calomel (standard) 

The Copper cell (Cu) could be portrayed as-

Calomel (standard) || Cu2+/Cu

From the nurst equation –

E=E– (2.303RTloga)/nF

Apparatus as well as chemicals required:

  1. Potentiometer
  2. standard cell
  3. Galvanometer
  4. Standard Calomel electrode
  5. Zinc electrode
  6. Cupper electrode
  7. 0.1M Solution of ZnSO4 and CuSO4

Procedure:

  1. 0.0001M, 0.001M and 0.01M solution is prepared.
  2. Then by the help of the calomel electrode and Potentiometer, we determine the potential of the Zn electrode at each concentration.
  3. For cupper, the above process should be repeated again.

Data of the Experiment:

emf of the ZnSO4 solution

Concentration of ZnSO4 emf
0.1 0.963
0.01 0.956
0.001 0.919
0.0001 0.833

emf for CuSO4 solution

Concentration of ZnSO4 emf
0.1 0.093
0.01 0.072
0.001 0.051
0.0001 0.043

Calculation: 

Ecell of Cu electrode

we will use the Nurst equation to determine the standard emf of the copper as well as zinc.

concentration emf mean activity co-efficient MCu2+. γ+ log(MCu2++)
0.0001 0.043 1.00 0.0001 -4
0.001 0.051 0.734 0.00734 -3.14
0.01 0.072 0.4 0.004 -2.397
0.1 0.083 0.161 0.0161 1.79

Ecell of Zn electrode

The Nurst equation will be used to determine both the normal zinc emf and copper emf.

concentration emf mean activity co-efficient MCu2+. γ+ log(MCu2++)
0.0001 0.963 1.00 0.0001 -4
0.001 0.956 0.734 0.00734 -3.14
0.01 0.919 0.4 0.004 -2.397
0.1 0.833 0.161 0.0161 1.79

Graphs

https://i0.wp.com/i.imgur.com/t9636Q1.png?resize=2479%2C3259&ssl=1standard electrode potential of cupper and zinc

Result:

From the above Experiment to determine the standard electrode potential of copper as well as zinc we get the two graphs.

Now From the graphs,

“The standard electrode potential of copper and zinc are 0.084 volts and 1.06 volt respectively.”

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FeSO4 + KMnO4 + H2SO4 = Fe2(SO4)3 + MnSO4 + H2O + K2SO4

NaCl + KMnO4 + H2SO4 = Cl2 + MnSO4 + Na2SO4 + K2SO4 + H2O

KMnO4 + H2O2 + H2SO4 = O2 + MnSO4 + K2SO4 + H2O

 

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