) Calculate the voltage of the cell you would expect to measure using your Hg standard values.   Ni/Ni+2             with         Sn/Sn+2.             _______________________ V   The Standard reduction potential values from Tables (using the Standard Hydrogen Electrode, SHE) are as follows: Sn+2 (aq)  +   2 e-   ®  Sn(s)                              -0.136 V   Ni+2 (aq)  +   2 e-   ®  Ni(s)                               -0.280 V   C) Calculate the voltage of the cell using the standard values from reference tables. Ni/Ni+2             with         Sn/Sn+2.     _______________________ V

3. Consider that the following half reaction is assigned a half cell voltage of 0.00 V.

            Hg⁺² (aq)  +  2 e^-  ®  Hg (l)                    E^o = 0.00 V

When this half-cell is paired with each of the following half-cells to form a complete cell in the laboratory, the following cell voltages are measured when the Hg cell is connected to the  (+) terminal, thus acting as the cathode.

             Hg “Standard” Cell Potentials

Ni/Ni⁺²                  with         Hg/Hg⁺².          1.134 V

Sn/Sn⁺²     with         Hg/Hg⁺².                     0.99 V

A) Calculate the reduction potentials using this Hg standard cell.

Ni⁺² (aq)  +  2 e^- ®  Ni(s)      ________________________ V (Hg Standard)

Sn⁺² (aq)  +  2 e^- ®  Sn(s)    ________________________ V (Hg Standard)

Mixed Cell Potentials

            Now consider combining the Ni/Ni⁺² and Sn/Sn⁺² half cells to produce a complete cell.

B) Calculate the voltage of the cell you would expect to measure using your Hg standard values.

Ni/Ni⁺²             with         Sn/Sn⁺².             _______________________ V

The Standard reduction potential values from Tables (using the Standard Hydrogen Electrode, SHE) are as follows:

Sn⁺² (aq)  +   2 e^-   ®  Sn(s)                              -0.136 V

Ni⁺² (aq)  +   2 e^-   ®  Ni(s)                               -0.280 V

C) Calculate the voltage of the cell using the standard values from reference tables.

Ni/Ni⁺²             with         Sn/Sn⁺².     _______________________ V

D) When the Sn⁺²/Sn half-cell is paired with Cd⁺²/Cd, a cell potential of 0.267 V is measured. In addition, tin metal is seen to precipitate out of solution.

Calculate the reduction potential of   Cd⁺² (aq)  +  2 e^-  ®  Cd(s) under the Hg standard and from the SHE standard.

Cd⁺² (aq)  +  2 e^- ®  Cd(s)    ________________________ V (Hg Standard)

Cd⁺² (aq)  +  2 e^- ®  Cd(s)   ________________________ V (SHE Standard)