Question

The oxidation state of chromium in the final product formed by the reaction between $KI$ and acidified potassium dichromate solution is

• A. +3
• B. +2
• C. +6
• D. +4

Answer 1

Answer: (A)

$C{r}_2{O}_7^{2-}+14H^{+}+6I^{-}\to 2C{r}^{3+}+7H_{2}O+3I_{2}C{r}_2{O}_7^{2-}$ is reduced to $C{r}^{3+}$.
Thus, final state of $Cr$ is $+3$.