Question

When potassium dichromate, $K_2{Cr}_2{O}_7$ is converted into $K_{2}Cr{O}_4$, the change in oxidation number of chromium is :

• A. $6$
• B. $0$
• C. $4$
• D. $3$

Answer 1

The correct option is B $0$

$\stackrel{+6}{K_2{Cr}_2{O}_7}\to \stackrel{+6}{K_2{Cr}^{}{O}_4}$. In this reaction no change in oxidation state of chromium

When potassium dichromate, $K_{2}C{r}_2{O}_7$ is converted into $K_{2}Cr{O}_4$, the change in oxidation number of chromium is zero. $K_{2}C{r}_2{O}_7$ and $K_{2}Cr{O}_4$ both have same oxidation number that is 6.

Option B is correct.