A voltaic cell consists of a Cd/Cd²⁺ electrode (E° = -0.40 V) and a Fe/Fe²⁺ electrode (E°= -0.44 V). If E_cell = 0 and the temperature is 25°C, what is the ratio [Fe²⁺]/[Cd²⁺]?

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Quizplus · Accepted Answer

The Nernst equation is:E_cell = E°_cell - (RT/nF)lnQwhere E_cell is the cell potential, E°_cell is the standard cell potential, R is the gas constant, T is the temperature in Kelvin, n is the number of moles of electrons transferred, F is the Faraday constant, and Q is the reaction quotient.At equilibrium, E_cell = 0, so:0 = E°_cell - (RT/nF)lnQSubstituting the given values:0 = -0.40 V - (-0.44 V) - (0.0257 V/K)(298 K)/(2 mol)(96,485 C/mol)lnQSolving for Q:Q = 1The reaction quotient is equal to the ratio of the concentrations of the products to the concentrations of the reactants. In this case, the products are Fe²⁺ and Cd, and the reactants are Cd²⁺ and Fe. Therefore, the ratio of the concentrations of the products to the concentrations of the reactants is:[Fe²⁺]/[Cd²⁺] = Q = 1Therefore, the ratio of [Fe²⁺] to [Cd²⁺] is 1.

A Voltaic Cell Consists of a Cd/Cd2+ Electrode (E° =

A Voltaic Cell Consists of a Cd/Cd²⁺ Electrode (E° =