`E^(@)` values of `Ni^(2+)//Ni and Cu^(2+)//Cu` are -0.25 V and +0.34 V respectively. Is the reaction:
`Ni+Cu^(2+)toNi^(2+)+Cu` spontaneous or not ? Give reason also.

Explanation

Hypothetical reaction is,
`Ni+Cu^(2+) to Ni^(2+)+Cu`
Half cel reaction are,
Oxidation: `Ni to Ni^(2+)+2e^(-)`
Reduction : `Cu^(2+)2e^(-) to Cu`
Overall: `Ni+Cu^(2+) to Ni^(2+)+Cu`
Cell representation
`Ni|Ni^(2+)||Cu^(2+)|Cu`
`EMF^(@)=E_(Cu^(2+)//Cu)^(@)-E_(Ni^(2+)//Ni)^(@)`
`=[0*34-(-0*25)]V=0*59V`
As `EMF^(@)gt0`, the reaction is spontaneous in the given direction.