Consider a voltaic cell made from the following redox reaction:
Mn (s) + Pb 2+ (aq) Mn 2+ (aq) + Pb (s) E cell = 1.15 V What is the value of E cell at 298 K under non-standard conditions when Pb 2+ = 1.5 10 - 4 M and Mn 2+ = 4.5 10 - 2 M?

Question

Consider a voltaic cell made from the following redox reaction:
Mn (s) + Pb 2+ (aq)  Mn 2+ (aq) + Pb (s) E cell = 1.15 V What is the value of E cell at 298 K under non-standard conditions when Pb 2+ = 1.5 10 - 4 M and Mn 2+ = 4.5 10 - 2 M?

Quizplus · Accepted Answer

The Nernst equation relates the measured cell potential to the standard cell potential and the concentrations of the reactants and products. It is given by Ecell = E°cell - (RT/nF)lnQ, where E°cell is the standard cell potential, R is the gas constant, T is the temperature in kelvin, n is the number of electrons transferred in the reaction, F is Faraday's constant, and Q is the reaction quotient.

In this case, we are asked to calculate the cell potential under non-standard conditions. The given concentrations allow us to calculate the reaction quotient: Q = [Mn2+]/[Pb2+] = (4.5 × 10-2)/(1.5 × 10-4) = 3.0 × 102.

Plugging in the values, we get:

Ecell = 1.15 - (0.0257 V/K)*(298 K)/(2)*(ln(3.0x10^2))
Ecell = 1.08 V

Therefore, the answer is B.

Consider a Voltaic Cell Made from the Following Redox Reaction