Question

Calculate the oxidation number of underlined elements in the following compounds:
$N{a}_2\left[\underset{--}{Fe}\right(CN{)}_5\left(N{O}^{+}\right)]$

• A. -2
• B. 3
• C. 1
• D. 2

Answer 1

The correct option is D 2

Let oxidation number of Fe be 'x' in $N{a}_2\left[Fe\right(CN{)}_5\left]\right(N{O}^{+}\left)\right]$
$\text{charge on}C{N}^{-}=-1$
$\text{charge on}N{O}^{+}=+1$
charge on co-ordination sphere=-2
$\Rightarrow x-5+1=-2$
$\Rightarrow x=+2$