Question

What is the equilibrium constant for the
reaction taking place at room temperature
(T = 25◦C) in the battery
Zn(s)| Zn2+(aq)|| Ce4+(aq)| Ce3+(aq) ?
Assume that the number of electrons transferred
in the reaction is n = 2.
Zn2+ + 2 e
− → Zn E
◦
red = −0.76 V
Ce4+ + e
− → Ce3+ E
◦
red = +1.61 V

Answer 1

2Ce4+ + 2e ==> 2Ce3+ 1.61 v.
Zn --> Zn2+ + 2e 0.76v
-----------------------
2Ce^4+ + 2e + Zn ==> Zn2+ +2e + 2Ce3+
Eocell = 1.61 + 0.76 = ? v.
Then nFEo = RTlnK
Substitute and solve for K.