Multiple Choice
Which of the following represents the balanced equation for the overall redox reaction between Fe³⁺(aq) and Cr(s) based on their standard reduction potentials?
319
views
20. Electrochemistry
Standard Reduction Potentials
Multiple Choice
Use the table of standard reduction potentials to calculate the equilibrium constant at standard temperature (25 °C) for the reaction: Fe(s) + Ni²⁺(aq) → Fe²⁺(aq) + Ni(s). Which of the following is the correct equilibrium constant (K)?
A
K = 1.0 x 10^1
B
K = 1.0 x 10^3
C
K = 1.0 x 10^2
D
K = 1.0 x 10^5
Verified step by step guidance1
Identify the half-reactions involved in the given redox reaction. The oxidation half-reaction is Fe(s) → Fe²⁺(aq) + 2e⁻, and the reduction half-reaction is Ni²⁺(aq) + 2e⁻ → Ni(s).
Look up the standard reduction potentials (E°) for each half-reaction from the table of standard reduction potentials. The standard reduction potential for Ni²⁺(aq) + 2e⁻ → Ni(s) is typically given, as well as for Fe²⁺(aq) + 2e⁻ → Fe(s).
Calculate the standard cell potential (E°cell) using the formula: E°cell = E°(reduction) - E°(oxidation). Substitute the values from the table to find E°cell.
Use the Nernst equation to relate the standard cell potential to the equilibrium constant (K). The equation is: ln(K) = (nF * E°cell) / (RT), where n is the number of moles of electrons transferred, F is Faraday's constant (96485 C/mol), R is the universal gas constant (8.314 J/mol·K), and T is the temperature in Kelvin (298 K for standard conditions).
Solve for K by rearranging the Nernst equation to K = e^((nF * E°cell) / (RT)). Calculate the exponent using the values for n, F, E°cell, R, and T, and then find K by taking the exponential of the result.
Related Videos
Related Practice
