Question

The oxidation number of Fe in $K_4\left[Fe{\left(CN\right)}_6\right]$ and $K_3\left[Fe{\left(CN\right)}_6\right]$ is respectively-

• A. +2 in both
• B. +3 in both
• C. +2 and +3
• D. +3 and +2

Answer 1

Answer: (C)

+2 and +3

$K_4\left[Fe{\left(CN\right)}_6\right]$

dissociates as

${4K}^{+}+{\left[Fe{\left(CN\right)}_6\right]}^{4-}So,x+6(-1)=-4x=+2$

$K_3\left[Fe{\left(CN\right)}_6\right]$

dissociates as

${3K}^{+}+{\left[Fe{\left(CN\right)}_6\right]}^{3-}=x+6(-1)=-3x=+3$