Question
THE E0 VALUES OF FOLLOWING REDUCTn Rxn R GIVEN
Fe 3+ (aq ) + e ----> Fe3+ (aq) E0= 0.771V
Fe2+(aq) + 2e----> Fe (s) E0 =0.447V
WHAT WILL BE THE FREE ENERGY CHANGE FOR D Rxn ?
Fe3+(aq) + 3E----> Fe(s)
ans +11.87kJ/MOL.
Joshi sir comment
Third reaction is the sum of 1st and 2nd so energy of 3rd will be the sum of energies of 1st and 2nd.
delta G = n1FE1 + n2FE2 = 1F(0.771) + 2F(0.447) = F(0.771+0.894) = 1.665F = 1.665*96368 = 160452.7 J = 38203.03 cal = 38.20303 cal
so total energy of the reaction
Fe3+(aq) + 3e- -------> Fe(s) is 38.203 cal
and value of n = 3 so per mole energy = 38.203/3