Calculate the cell emf for the following reaction at 25°C: 2Ag⁺(0.010 M)+ H₂(1 atm)$\rarr$ 2Ag(s)+ 2H⁺(pH = 10.0)

Question

Quizplus · Accepted Answer

First, we need to write the two half-reactions for the redox reaction:
Ag2S(s) + 2e- -> 2Ag(s) E° = 0.73 V
H+ + e- + Ag2S(s) -> AgS(s) + H2O E° = 0.65 V (reverse reaction)
Adding the two half-reactions above, we get:
2AgS(s) + 2H+ -> 2Ag(s) + H2S
The overall reaction is:
2AgS(s) + S2- + 2H+ -> 2Ag(s) + H2S
Now we can calculate the cell EMF using the Nernst equation:
Ecell = E° - (RT/nF)ln(Q)
where E° = 0.73 V, R = 8.314 J/mol·K, T = 298 K, n = 2 (since two electrons are involved), F = 96485 C/mol.
Q = [Ag+]2/[H+]2[S2-] = (1.0×10-2 M)2/(1.0×105 Pa)[1]
(Note that the concentration of H+ can be calculated from the given pH of 10.0.)
Substituting the values into the Nernst equation, we get:
Ecell = 0.73 V - (8.314 J/mol·K / (2 × 96485 C/mol)) ln[(1.0×10-2 M)2/(1.0×105 Pa)] = 1.27 V
Therefore, the answer is B.

Calculate the Cell Emf for the Following Reaction at 25°C →\rarr→

Calculate the Cell Emf for the Following Reaction at 25°C $\rarr$