Question

In which of the following compounds transition metal has zero oxidation state?

• A. ${CrO}_5$
• B. ${NH}_2\cdot {NH}_2$
• C. ${NOClO}_4$
• D. $[Fe\left(CO{)}_5\right]$

Answer 1

Answer: (D)

$[Fe\left(CO{)}_5\right]$

Solution:

$\left(1\right)$ In option $B$ & $C$ there is no transition metals so elimimated

$\left(2\right)$ In $\left[Fe\right(CO{)}_5]$ carbon monoxide is a natural ligand, therefore no involvement of $Fe$ electrons in complex, $Fe$ has zero oxidation state.

$\therefore$ Option $D$ is correct answer.