Nernst Equation Calculator

Nernst Equation Calculator

The Nernst Equation Calculator computes the reduction potential of a half-cell or full cell reaction under non-standard conditions. The Nernst equation relates electrode potential to standard potential, temperature, and the activities of oxidized and reduced species.

$$E = E_0 - \frac{RT}{zF} \ln\frac{[\text{red}]}{[\text{ox}]}$$

where $E$ is the reduction potential (V), $E_0$ is the standard reduction potential (V), $R$ is the gas constant (8.314 J/(K·mol)), $T$ is temperature in Kelvin, $z$ is the number of electrons transferred, $F$ is Faraday's constant (96,485 C/mol), and $[\text{red}]/[\text{ox}]$ is the ratio of reduced to oxidized species activities or concentrations.

Example: For a cell with $E_0 = 2.25$ V at 25 °C, $z = 2$, and $[\text{Mg}^{2+}]/[\text{Pb}^{2+}] = 0.020/0.200 = 0.1$, the reduction potential is $E = 2.28$ V.

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