Question

What is the oxidation state of central atom in $\left[Ni\right(CN{)}_4{]}^{2-}$ ?

• A. $0$
• B. $1$
• C. $2$
• D. $3$

Answer 1

The correct option is C $2$

${\left[Ni{\left(CO\right)}_4\right]}^{2-}$

Central atom $=Ni$

Oxidation state of $CO$ in general $=-1$

Applying formula, $\text{Sum of total oxidation state of all atoms}=\text{Overall charge on the compound}.$

Let oxidation state of $Ni=xx+4(-1)=-2,x=+2$

$\therefore$ Oxidation state of $Ni=+2.$