Calculate the oxidation number of Ni in `K_(2)[Ni(CN)_(4)]` .

Explanation

Let the charge on Ni be x
Charge on `CN^( ᶱ)=-1`
`K_(2)[Ni(CN)_(4)]rarr2K^(o+)+[Ni(CN)_(4)]^(2-)`
Charge on complex ion , `[Ni (CN)_(4))_(4)]^(2) = -2`
`implies x + 4 x (-1) = -2`
`implies x = +2`
Oxidation number of Ni is II .