Question

What is the oxidation state of iron ($Fe$) in $\left[Fe\right(CN{)}_{5}NO{]}^{2-}$?
[Note: Write the correct answer in modulus of oxidation state]

Answer 1

Let the oxidation state of $Fe$ in $\left[Fe\right(CN{)}_{5}NO{]}^{2-}$ be $x$.

We know that ligands, $C{N}^{-}$ and $NO$ contain $-1$ and $+1$ charge, respectively.

So,
$x+5(-1)+1=-2$
$x=+2$

Hence, the oxidation state of $Fe$ in $\left[Fe\right(CN{)}_{5}NO{]}^{2-}$ is +2.

The correct answer would be $|+2|=2$