Question

A complex compound in which the oxidation number of a metal is zero is

• A. $K_4[Fe(CN)_6]$
• B. $K_3[Fe(CN)_6]$
• C. $[Ni(CO)_4]$
• D. $[Pl(NH_3)_4]Cl_2$

Answer 1

Answer: (C)

$[Ni(CO)_4]$

Answer 2

$CO$ is a neutral ligand, so the oxidation state of metal in metal carbonyls is always zero.

$\left[N i(C O)_{4}\right]$
$x+(0 \times)=0$
$x=0$