Question

Calculate the oxidation number of underlined element in the given compound.
$K\left[\underset{–}{Co}\right(C_2{O}_4{)}_2\left(N{H}_3{)}_2\right]$

• A. 5
• B. 6
• C. 2
• D. 3

Answer 1

The correct option is D 3

So, ionic form is ${{\left[Co\right(C_2{O}_4)}_2{{(NH}_3)}_2]}^{-}$.

Since, ${NH}_3$ is a neutral ligand. So, charge on ${NH}_3$ = 0

$C_2{O}_4$ is a negative ligand. Change on $C_2{O}_4$ = -2

Now, suppose oxidation state of $Co$ is $x$.

So, $x+2\times (-2)+2\times 0=-1x-4=-1x=+3$.

So, correct answer is option D.