The standard cell potential (E°_cell) for the reaction below is +1.10 V. The cell potential for this reaction is V when the concentration of [Cu²⁺] = 1.0 × 10^-⁵M and [Zn²⁺] = 1.0 M.

Question

Quizplus · Accepted Answer

The Nernst equation can be used to calculate the cell potential under non-standard conditions:

Ecell = E°cell - (RT/nF)ln(Q)

where R is the gas constant, T is the temperature in Kelvin, n is the number of electrons transferred, F is Faraday's constant, and Q is the reaction quotient.

The reaction quotient can be calculated using the concentrations of the reactants and products raised to their stoichiometric coefficients.

For the given reaction:

Cu2+(aq) + Zn(s) → Cu(s) + Zn2+(aq)

the reaction quotient can be written as:

Q = [Cu2+]/[Zn2+]

Substituting the given concentrations and the standard cell potential into the Nernst equation:

Ecell = 1.10 V - (0.0257 V/n)ln([Cu2+]/[Zn2+])
Ecell = 1.10 V - (0.0257 V/2)ln(1.0 x 10^-15/1.0)
Ecell = 0.95 V

Thus, the cell potential is 0.95 V when the concentrations of [Cu2+] = 1.0 × 10^-15 M and [Zn2+] = 1.0 M. Therefore, the correct answer is B.

The Standard Cell Potential (E°cell) for the Reaction Below Is

The Standard Cell Potential (E°_cell) for the Reaction Below Is