Find the equilibrium constant that the reaction
`In^(2+)+Cu^(2+)underset(larr)rarrIn^(3+)+Cu^(+)` at 298 K
Given
`E_(Cu^(2+)//Cu^(+))=0.15V, E_(In^(2+)//In^(+))^(@)=-0.40V`
`E_(In^(3+)//In^(+))^(@)=+0.42V`

Explanation

The required reaction can be obtained in the following way.
`{:(Cu^(2+)+e^(-)rarrCu^(+),DeltaG^(@) =- 0.15F),(,(DeltaG^(@) =- nFE^(@))),(In^(2+)+e^(-)rarrIn^(+),DeltaG^(@)=+0.40F),(In^(+)rarrIn^(3+)+2e^(-),DeltaG^(@)=-0.84F):}`
On adding
`Cu^(2+) +In^(2+) rarr In^(3+) +Cu^(+), E^(@) =- 0.59F`
Now we know that `-n FE^(@) =- 0.59F`
or `-E_(cell)^(@) = E_(cell)^(@) - (0.0591)/(n)logK_(c)`.
`E_(cell) = 0` then `E_(cell)^(@) = (0.0591)/(n)logK_(c)`.
log `K_(c) = (0.59)/(0.0591) = 10, K_(c) = 10^(10)`