A voltaic cell is constructed with two Zn²⁺-Zn electrodes, where the half-reaction is Zn²⁺ + 2e^- → Zn (s) E° = -0.763 V
The concentrations of zinc ion in the two compartments are 4.50 M and 1.11 × 10^-2 M, respectively. The cell emf is ________ V.

Question

Quizplus · Accepted Answer

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

Ecell = E°cell - (RT/nF)ln(Q)

Where:
R = gas constant = 8.314 J/mol·K
T = temperature = 298 K
n = number of electrons transferred in the balanced equation
F = Faraday constant = 96,485 C/mol
Q = reaction quotient = [Zn2+][S2-]/[ZnS]

First, we need to write the balanced equation for the cell reaction:

ZnS + Zn2+ → 2 Zn + S2-

Then, we can calculate the reaction quotient for the given concentrations:

Q = (1.11 × 10^-12)/(4.50) = 2.47 × 10^-13

Now, we can use the Nernst equation to calculate the cell potential:

Ecell = -0.763 V - (0.0257/2)ln(2.47 × 10^-13) = 0.0772 V

Therefore, the answer is C: 0.0772 V.

A Voltaic Cell Is Constructed with Two Zn2+-Zn Electrodes, Where

A Voltaic Cell Is Constructed with Two Zn²⁺-Zn Electrodes, Where