Question

The oxidation state of $Ni$ in $N(CO{)}_4$ is

• A. zero
• B. $-2$
• C. $+2$
• D. $+4$

Answer 1

Answer: (A)

Let the oxidation number of $Ni$ is $x$ in $Ni(CO{)}_4$.
So, $x+4(0)=0$
$x=0$
Oxidation number of a metal in carbonyl complex is always zero.