Question

The pair of compounds having metals in their highest oxidation state is

• A. $Mn{O}_2,FeC{l}_3$
• B. $[Mn{O}_4{]}^{-},Cr{O}_{2}C{l}_2$
• C. $\left[Fe\right(CN{)}_6{]}^{3-},\left[Co\right(CN{)}_3]$
• D. $[NiC{l}_4{]}^{2-},[CoC{l}_4{]}^{-}$

Answer 1

The correct option is B $[Mn{O}_4{]}^{-},Cr{O}_{2}C{l}_2$

a. The oxidation state of $Mn$ in $Mn{O}_2$ is +4
The oxidation state of $Fe$ in $FeC{l}_3$ is +3

b) The oxidation state of $Mn$ in $[Mn{O}_4{]}^{-}$ is +7
The oxidation state of $Cr$ in $Cr{O}_{2}C{l}_2$ is +6

c) The oxidation state of $Fe$ in $\left[Fe\right(CN{)}_6{]}^{3-}$ is +3
The oxidation state of $Co$ in $\left[Co\right(CN{)}_3]$ is +3

d) The oxidation state of $Ni$ in $[NiC{l}_4{]}^{2-}$ is +2
The oxidation state of $Co$ in $[CoC{l}_4{]}^{-}$ is +3

So the correct option is (b)