8.26 :  Using the standard electrode potentials given in the Table 8.1, predict if the reaction between the following is feasible:
(a) Fe3+(aq) and I-(aq)
(b) Ag+(aq) and Cu(s)
(c) Fe3+ (aq) and Cu(s)
(d) Ag(s) and Fe3+(aq)
(e) Br2aq and Fe2+(aq)

NEETprep Answer:
(a) The possible reaction between Feaq3++l-aq
2Fe3-aq+2l-aq2Fe2+aq+l2s is given by,
Oxidation half equation :  2l-aql2s+2e-:E°=-0.54V
Reductionhalfequation:Fe3+aq+e-Fe2-aq×2;E°=+0.77V2Fe3+aq+2l-aq2Fe2+aq+I2s;E°=+0.23V
E° for the overall reaction is positive. Thus, the reaction between Fe3+aqandI-aqis feasible.
(b)  The possible reaction between Ag+aq+Cus is given by,
2Ag+aq+Cus2Ags+Cu2+aq
Oxidation half equation :  CusCu2+aq+2e-:E°=-0.34V
Reductionhalfequation:Ag+aq+e-Ags×2;E°=+0.80V2Ag+aq+Cus2Ags+Cu2+;E°=+0.46V
E° positive for the overall reaction is positive. Hence, the reaction between Ag+aqandCus is feasible.
(c) The possible reaction between Fe3+aqandCus is given by,
2Fe3+aq+Cus2Fe2+s+Cu2+aq
Oxidation half equation :   CusCu2+aq+2e-;E°=-0.34V
Reductionhalfequation:Fe3+aq+e-Fe2+s×2;E°=+0.77V2Fe3+aq+Cus2Fe2+s+Cu2+aq;E°=+0.43V
E° positive for the overall reaction is positive. Hence, the reaction between Fe3+aqandCus is feasible.
(d) The possible reaction between AgsandFe3+aq
Ags+2Fe3+aqAg+aq+Fe2+aq is given by,
Oxidation half equation : AgsAg+aq+e-;E°=-0.80V
Reductionhalfequation:Fe3+aq+e-Fe2+aq;E°=+0.77VAgs+Fe3+aqAg+aq+Fe2+aq;E°=-0.03V
Here, E° for the overall reaction is negative. Hence, the reaction between AgsandFe3+aq is not feasible.
(e)  The possible reaction between Br2aqandFe2+aq is given by,
Br2s+2Fe2+aq2Br-aq+2Fe3+aq
Oxidation half equation :  Fe2+aqFe3+aq+e-]×2;E°=-0.77
Reductionhalfequation:Br2aq+2e-2Br-aq;E°=+1.09VBr2aq+2Fe2+aq2Br-aq+2Fe3+aq;E°=-0.32V
Here, E° for the overall reaction is positive. Hence, the reaction between Br2aqandFe2+aq is feasible.