Question

Oxidation number of $Cr$ in $C{r}_2{O}_7^{2-}$ is

• A. $+2$
• B. $+4$
• C. $+6$
• D. $+7$

Answer 1

Answer: (C)

Let the oxidation number of $Cr$ in $C{r}_2{O}_7^{2-}$ is $x$.
$2x+\left(7\times -2\right)=-2$
$2x=-2+14$ or $x-12/2=+6$