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Predict if the reaction between the followig is feasible: (i) Fe^(3+)(aq) and I^(-)(aq) (ii) Ag^(+)(aq) and Cu (iii) Fe^(3+) and Br^(-1)(aq) (iv) Ag(s) and Fe^(3+)(aq) (v) Br_(2)(aq) and Fe^(2+)(aq). Given standard electrode potential: E_(1//2I_(2),I^(-))^(@)=-0.541,E_(Cu^(2+),Cu)^(@)=0.34V E_(1//2Br_(2),Br^(-))^(@)=1.09V,E_(Ag^(+),Ag)^(@)=+0.80V,E_(Fe^(3+),Fe^(2+))^(@)=+0.77V |
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Answer» Solution :A reaction FEASIBLE if EMF of the cell reaction is +ve <BR> (i) `Fe^(3+)(aq)+I^(-)(aq)toFe^(2+)(aq)+(1)/(2)I_(2)` i.E., `Pt|I_(2)|I^(-)(aq)||Fe^(3+)(aq)|Fe^(2+)(aq)|Pt` `thereforeE_(cell)^(@)=E_(Fe^(3+),Fe^(2+))^(@)-E_(1//2I_(2),I^(-))^(@)=0.77-0.54=0.23V` (Feasible) (ii) `Ag^(+)(aq)+CutoAg(s)+Cu^(2+)(aq),` i.e., `Cu|Cu^(2+)(aq)||Ag^(+)(aq)|Ag` `E_(cell)^(@)+E_(Ag^(+),Ag^(-))^(@)-E_(Cu^(2+),Cu)^(@)=0.80-0.34=0.46V` (Feasible) (III) `Fe^(3+)(aq)+Br^(-)(aq)toFe^(2+)(aq)+(1)/(2)Br_(2),E_(cell)^(@)=0.77-1.09=-0.32V` (Not feasible) (IV) `Ag(s)+Fe^(3+)(aq)toAg^(+)(aq)+Fe^(2+)(aq)E_(cell)^(@)=0.77-0.80=-0.03V` (Not feasible) (v) `(1)/(2)Br_(2)(aq)+Fe^(2+)(aq)toBr^(-)+Fe^(3+),E_(cell)^(@)=1.09-0.77=0.32V` (Feasible) |
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