Question

In which of the following compounds, iron has the lowest oxidation state?

• A. $FeS{O}_4(N{H}_4{)}_{2}S{O}_4.6H_{2}O$
• B. $K_4\left[Fe\right(CN{)}_6]$
• C. $Fe(CO{)}_5$
• D. $F{e}_{0.94}O$

Answer 1

Answer: (C)

$Fe(CO{)}_5$

The oxidation state of following compounds are

$\left(i\right)\stackrel{+2}{Fe}\stackrel{-2}{\left(S{O}_4\right)}.\stackrel{+2}{(N{H}_4{)}_2}\stackrel{-2}{S{O}_4}.6H_{2}O]$

$\Rightarrow +2$ oxidation state.

$\left(ii\right)K_4\left[\stackrel{n}{Fe}\stackrel{-6}{(CN{)}_6}\right]$

$n-6=-4$

$\Rightarrow +2$ Oxidation state.

$\left(iii\right)\stackrel{n}{Fe}(CO{)}_5^o$

$\Rightarrow n=0$

$\left(iv\right)F{e}_{0.94}O\Rightarrow +ve$ oxidation state.

The least oxidation state is for $Fe(CO{)}_5$