The overall reaction 2Co³⁺(aq) + 2Cl^-(aq) $\rarr$2Co²⁺(aq) + Cl₂(g) has the standard cell voltage E^$\circ$_cell= 0.46 V. Given E^$\circ$ = 1.36 V for the reaction Cl₂(g) + 2e^- $\rarr$ 2Cl^-(aq), calculate the standard reduction potential for the following the half reaction at 25^$\circ$C: Co³⁺ + e^- $\rarr$ Co²⁺

Question

Quizplus · Accepted Answer

Using the Nernst equation:

EF1F1F1S1F1F1F1red = EF1F1F1S1F1F1F10 - (RT / nF) ln(K)

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

Since the overall reaction is the sum of the two half-reactions and the stoichiometry is balanced such that the number of electrons transferred is the same, we can write:

EF1F1F1S1F1F1F1cell = EF1F1F1S1F1F1F1red(CoS1U1P13+) - EF1F1F1S1F1F1F1red(ClS1U1P1-S1S1P0)

Solving for EF1F1F1S1F1F1F1red(CoS1U1P13+), we get:

EF1F1F1S1F1F1F1red(CoS1U1P13+) = EF1F1F1S1F1F1F1cell + EF1F1F1S1F1F1F1red(ClS1U1P1-S1S1P0)
                          = 0.46 V + 1.36 V
                          = 1.82 V

Therefore, the answer is A.

The Overall Reaction 2Co3+(aq) + 2Cl-(aq) →\rarr→ 2Co2+(aq) + Cl2(g) Has the Standard Cell Voltage E

The Overall Reaction 2Co³⁺(aq) + 2Cl^-(aq) $\rarr$ 2Co²⁺(aq) + Cl₂(g) Has the Standard Cell Voltage E