Exercise 6 | Electrochemistry

What is the standard cell voltage at 25°C for the following galvanic cell:

Ga | Ga3+ (10-5 M) || Ag+ (10-3 M) | Ag?


Data: E0red (Ga3+/Ga) = - 0.549 V

E0red (Ag+/Ag) = 0.7996 V

Half reactions:

Ga (s) → Ga3+ (aq) + 3 e-

Ag+ (aq) + e- → Ag (s)

 


Nernst equation:


Oxidation half reaction:

Eox = E0ox (Ga3+/Ga)  –  0.02570νe ln [Ga3+]

Eox = - E0red (Ga3+/Ga) – 0.02570νe ln [Ga3+]

Eox = 0.549 – 0.025703 x ln 10-5

Eox = 0.648 V

 

Reduction half reaction:

Ered = E0red (Ag+/Ag) – 0.02570νe ln 1Ag+

Ered = 0.7996 + 0.02570 ln 10-3

Ered = 0.622 V


Standard cell voltage Ecell = Eox + Ered = 1.27 V