Solve this:
The standard emf of the following cell:
Cd(s)|CdCl2(aq) (0.10 M)||Cl-| AgCl(s)|Ag(s)
In which the cell reaction is 2AgCl(s) + Cd(s) 2Ag(s) +Cd2+ + 2Cl-(aq) is 0.6915 V at 100 C and 0.6753 V at 250C. The H of reaction at 250C is
(A) -192.5 kJ                                      (B) -234.7 kJ
(C) 123.5 kJ                                       (D) -167.26 kJ

Dear Student,


1. The formula used is Gibbs Helmoltz equation :

       
G=H-TS2. From the data in question: G1(283K) =-nFE=-2×96500×0.6195=11.96 kJ G2(298K) = -nFE=-2×96500×0.6753=13.03 kJ3. Using equation 1 :    11.96 kJ =    H-283S            ...(1)- 13.03 kJ =-H+298S          ...(2)we get,  S =-572 JK-1   H= 123.5 kJ         
Regards,

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