The equilibrium constant for the reaction is:
2Fe3++3I⊖⇌Fe3++Ce3+
Given :
E⊖Ce4+1Ce3+ = 1.44 V
E⊖Fe3+1Fe2+= 0.68 V.For the cell reaction :
Fe2++Ce4+⇌Fe3++Ce3+
Half cell reaction are :
At equilibrium,
E⊖cell=0.0591nlogkeq (because at equilibrium, Ecell=0).
+ 0.76 = 0.05911logKeq
logKeq=0.760.0591=12.895⇒Keq=7.236×1012