Question

The charge on the central metal ion in the complex $[Ni(CO)_4]$ is

• A. +2
• B. +4
• C. 0
• D. +3
• E. +1

Answer 1

Answer: (C)

Let in $[Ni(C0)_4]$, oxidation state (charge) of Ni is x.
$\, \, \, \, \, \, \, \, \, \, \, \, \, Ni(CO)_4$ $\, \, \, \, \, \, \, \, \, \, \, x + (0 \times 4) = 0 [\because$ Oxidation state of CO= O]
$\therefore \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, $x=0
In metal carbonyl, oxidation state of metal is always zero.