Question

Potassium dichromate is a good oxidizing agent, in acidic medium the oxidation state of chromium changes by:

• A. $2$
• B. $3$
• C. $4$
• D. $5$

Answer 1

The correct option is B $3$

Dichromate oxidizes to $C{r}^{+3}$ from $C{r}_2{O}_7^{-2}$ in acidic medium according to the reaction

$C{r}_2{O}_7^{-2}+14H^{+}+6e^{-}\to 2C{r}^{+3}+7H_{2}O$

In dichromate, Chromium is in +6 oxidation state and on the RHS we have Cr in +3 state. So the change is from +6 to +3 in acidic medium. So oxidation state changes by 3 units.

So, option Bis correct.