18.8
a) Ni^{2+} + 2e^{-} \leftrightarrows Ni^{0} E⁰ = -0.25V
E = -0.25V – \frac{0.0592}{2} \times log(\frac{1}{0.0883M}).
E = -0.281V Anode
b) AgI + e^{-} \leftrightarrows Ag + I^{-} E⁰ = -0.151V
E = -0.151V – \frac{0.0592}{1} \times log(0.0898M).
E = -0.089V Anode
c) O_2 + 4H^{+} + 4e^{-} \leftrightarrows H_2O E⁰ = 1.229V
E = 1.229V – \frac{0.0592}{4} \times log(\frac{1}{(2.50\times 10^{-4})^4(\frac{780}{760})}).
E = 1.016V Cathode
d) Sn^{4+} + 2e^{-} \leftrightarrows Sn^{2+} E⁰ = 0.154V
E = 0.154V – \frac{0.0592}{2} \times log(\frac{0.0893M}{0.215M}).
E = 0.165V Cathode
e) Ag(S_2O_3)_2^{3-} + e^{-} \leftrightarrows Ag + 2(S_2O_3)^{2-} E⁰ = 0.017V
E = 0.017V – \frac{0.0592}{1} \times log(\frac{(0.1035M)^2}{0.00891M}).
E = 0.012V Cathode