Using the standard electrode potential valuesl predict if the reaction between the following is feasible :
(i) Fe3+(aq) and I−(aq)
(ii) Ag+(aq) and Cu(s)
(iii) Fe3+(aq) and Br−(aq)
(iv) Ag(s) and Fe3+(aq)
(v) Br2(aq) and Fe2+(aq)
Given standard electrode potentials
E∘12t21−=+0.541VE∘(Cu2+Cu)=+0.34VE∘(12Br2Br−)=+1.09VE∘(Ag+Ag)=+0.80VE∘(Fe3+Fe2+)=+0.77V
(i) A reaction is feasible, if its Ecellcell value is positive.
Fe3+(aq)+I−(aq)→Fe2+(aq)+12I2(g)
E∘cell=E∘cell(Fe3+Fe26)−E∘cell12I2I−=0.77−0.54=0.23V
The reaction is feasible.
(ii) A reaction is feasible, if its Ecellcell value is positive.
Cu(s)+2Ag+(aq)→2Ag(s)+Cu2+(aq)
E∘cell=E∘cell(Ag+Ag0)−E∘cell(Cu2+Cu)=0.80−0.34=0.46V
The reaction is feasible
(iii) A reaction is feasible, if its Ecellcell value is positive.
Fe3+(aq)+Br−(aq)→Fe2+(aq)+12Br2(g)
E∘cell=E∘cell(Fe3+Fe2+)−E∘cell(12Br2Br−)=0.77−1.09=−0.32V
The reaction is not feasible
(iv) A reaction is feasible, if its Ecellcell value is positive.
Ag(s)+Fe3+→Ag+(aq)+Fe2+(aq)
E∘cell=E∘Fe3+Fe2+−E∘Ag+Ag=0.77−0.80=−0.03V
The reaction is not feasible
(v) A reaction is feasible, if its Ecellcell value is positive.
12Br2(aq)+Fe2+(aq)→Br−(aq)+Fe3+(aq)
E∘cell=E∘12Br2Br−−E∘Fe3+Fe2+=1.09−0.77=0.32V
The reaction is feasible.