Which of the following reactions would have the smallest value of K at 298 K? A) A + B → C; E°_cell = +1.22 V B) A + 2 B → C; E°_cell = +0.98 V C) A + B → 2 C; E°_cell = -0.030 V D) A + B → 3 C; E°_cell = +0.15 V E) More information is needed to determine.

Question

Quizplus · Accepted Answer

The value of K is related to ΔG° through the equation ΔG° = -RT ln K, where R is the universal gas constant and T is the temperature in Kelvin. At constant temperature, the reaction with the smallest ΔG° will have the largest K.
ΔG° can be calculated using the equation ΔG° = -nFE°, where n is the number of moles of electrons transferred, F is the Faraday constant, and E° is the standard reduction potential. The larger the magnitude of E° (positive or negative), the larger the magnitude of ΔG° (in absolute value).
Option C has the smallest magnitude of E° (negative), which implies the smallest magnitude of ΔG° and the largest value of K among the given reactions.

Which of the Following Reactions Would Have the Smallest Value