Question

Oxidation number of Cr in $K_{3}Cr{O}_8$ is $+5$.
If true enter 1, else enter 0.

• A. 1

Answer 1

The correct option is A 1
Let $x$ be the oxidation number of Cr in $K_{3}Cr{O}_8$.
Since the overall
charge on the complex is $0$, the sum of oxidation states of all elements in
it should be equal to $0$.
The complex has peroxide linkages, so each oxygen has oxidation number of $-1$.
Therefore, $3(+1)+x+8(-1)=0$
$x=+5$
Hence, the oxidation number of Cr in $K_{3}Cr{O}_8$ is $+5$.
The structure is shown below: