Find the equilibrium constant for the reaction:
`Cu^(2+)+In^(2+)hArr Cu^(+)+In^(3+)`
Given : `E_(Cu^(2+)|Cu^(+))^(@)=0.15V, E_(In^(2+)|In^(+))^(@)=-0.4V,`
`E_(In^(3+)|In^(+))^(@)=-0.42V`

Explanation

We know, `DeltaG^(@)=-nFE^(@)`
`{:((1),Cu^(2+)+e,rarr,Cu^(+),,DeltaG_(1)^(@)=-0.15F),((2),In^(2+)+e,rarr,In^(+),,DeltaG_(2)^(@)=+0.4F),((3),In^(2+)+2e,rarr,In^(+),,DeltaG_(3)^(@)=+0.84F):}`
Adding equation (1) and (2) and subtracting equation (3) we get,
`Cu^(2+)+In^(2+)rarrCu^(+)+In^(3+)`
`DeltaG^(@)=DeltaG_(1)^(@)+DeltaG_(2)^(@)-DeltaG_(3)^(@)=-0.59F`
`DeltaG^(@)=-2.303RTlogK_(eq)therefore -0.59F=-2.303RT log K_(eq)`
`"or, "log K_(eq)=(0.59xx96500)/(2.303xx8.314xx298)~~10 " "therefore" "K_(eq)=10^(10)`