Read the following passage for the evaluation of `E^(@)` when diffe
Channel: Doubtnut
Date: 16/02/2020

Read the following passage for the evaluation of `E^(@)` when different number of electrons are involved. Consider addition of the following half reactions (1) `Fe^(3+)(aq)+3e^(-)rarr Fe(s) E_(1)^(@)=0.45V` (2) `Fe(s)rarr Fe^(2+)(aq)+2e^(-) E_(2)^(@)=-0.04V` (3) `Fe^(3+)(aq)+e^(-)rarr Fe^(2+)(aq) E_(3)^(@)= ?` Because half-reactions (1) and (2) contains a different number of electrons, the net reaction (3) is another half-reaction and `E_(3)^(@)` can\'t be obtained simply by adding `E_(1)^(@)` and `E_(3)^(@)`. The free - energy changes however, are additive because G is a state function : `Delta G_(3)^(@)=Delta G_(1)^(@)+Delta G_(2)^(@)` Standard electrode potential for the half-cell `Fe^(3+)//Fe^(2+)` of the reaction (3) is :