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?