The standard electrode potential of cupper and zinc is a important experiment arround the world. This experiment is valuable for the general chemistry as well as the applied chemistry. Values for **standard electrode potentials** are most often tabulated at 25 °C and with reference to astandard hydrogen electrode (SHE).

## Determination of the standard electrode potential of cupper and zinc:

To determine the standard electrode potential of cupper 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-

**E _{cell }= E_{cathode(red)} – E_{anode(red)}**

The cell for zinc (Zn) can be represented as-

**Zn/Zn ^{2+} || Calomel (standard) **

**Calomel (standard) || Cu ^{2+}/Cu**

From the nurst equation –

**E=E ^{0 }– (2.303RTloga)/nF**

**Apparatus as well as chemicals required:**

- Potentiometer
- standard cell
- Galvanometer
- Standard Calomel electrode
- Znic electrode
- Cupper electrode
- 0.1M Sloution of ZnSO
_{4}and CuSO_{4}

## Procedure:

- 0.0001M, 0.001M and 0.01M solution is prepaired.
- Then by the help of the calomel electrode and Potentiometer we determin the potential of the Zn electrode at each concentration.
- For cupper the above process should be repeat again.

**Data of the Experiment:**

**emf of the ZnSO _{4} 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:

**E _{cell} of Cu electrode**

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

concentrarion | emf | mean activity co-efficient | M_{Cu2+. }γ^{+} |
log(M_{Cu2+}xγ^{+}) |

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 |

**E _{cell} of Zn electrode**

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

concentrarion | emf | mean activity co-efficient | M_{Cu2+. }γ^{+} |
log(M_{Cu2+}xγ^{+}) |

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

## Result:

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

Now From the graphs,

**“The standard electrode potential of cupper and zinc are 0.084 volt and 1.06 volt respectively.”**

**Click on the reaction to learn balancing redox reaction easily by ion electron method**

**K**_{2}Cr_{2}O_{7}+ FeSO_{4}+ H_{2}SO_{4}= Cr_{2}(SO_{4})_{3}+ Fe_{2}(SO_{4})_{3}+ K_{2}SO_{4}+ H_{2}O (click here)**FeSO**_{4}+ KMnO_{4}+ H_{2}SO_{4}= Fe_{2}(SO_{4})_{3}+ MnSO_{4}+ K_{2}SO_{4}+ H_{2}O (click here)**NaCl + KMnO**_{4}+ H_{2}SO_{4}^{ }= Cl_{2}^{ }+ MnSO_{4}+ Na_{2}SO_{4}+ K_{2}SO_{4}+ H_{2}O (click here)**H2O2 + KMnO4 + H2SO4 = O2 + MnSO4 + K2SO4 + H2O (click here)**

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