The Nernst equation is applicable not just to cell reactions, but also to half-reactions. Consider the following half-reaction, 

2 Hg²⁺(aq) + 2 e⁻ → 2 Hg₂²⁺(aq)       E° = 0.92 V

Using the Nernst equation, what is its potential at 25 °C if [Hg²⁺] = [Hg₂²⁺] = 0.15 M?

The overall reaction for a a voltaic cell is Co²⁺(aq) + Ni(s) → Co(s) + Ni²⁺(aq). The cell potential is +0.16 V when the concentration of Co²⁺ in the cathode is 1.5 M. Calculate the concentration of Ni²⁺ in the anode half-cell for this case.

Ni²⁺(aq) + 2 e^– → Ni(s)     E° = –0.26 V
Co²⁺(aq) + 2 e^– → Co(s)   E° = –0.28 V

A voltaic cell initially consists of a 0.0250 M Mg/Mg²⁺ half-cell and a 1.32 M Ag/Ag⁺ half-cell. Calculate the cell potential when the Ag⁺ has already dropped to 3.18 V.

A voltaic cell initially consists of a 0.0250 M Mg/Mg²⁺ half-cell and a 1.32 M Ag/Ag⁺ half-cell. Calculate the cell potential when the Ag⁺ has already dropped to 0.50 M.

Calculate the pH needed for a standard hydrogen electrode to have an electrode potential of -0.153 V