Question

In acidic medium, $H_2{O}_2$ changes $C{r}_2{O}_7^{-2}$ to $Cr{O}_5$ which has two ($-O-O-$) bonds oxidation state of $Cr$ in $Cr{O}_5$ is:

• A. 5
• B. 3
• C. 6
• D. -10

Answer 1

Answer: (C)

6

In acidic medium, $H_2{O}_2$ changes $C{r}_2{O}_7^{-2}$ to $Cr{O}_5$ which has two ($-O-O-$) bonds.

$K_{2}C{r}_2{O}_7+H_{2}S{O}_4+4H_2{O}_2\to 2Cr{O}_5+K_{2}S{O}_4+5H_{2}O$.

The oxidation state of $Cr$ in $Cr{O}_5$ is +6.

Let $X$ be the oxidation state of $Cr$ in $Cr{O}_5$.
$X+(-2)+2(-2)=0$
$X=+6$.

Hence, the correct option is $C$.