Question

What is the change in oxidation state of chromium when potassium dichromate is treated with dilute sulphuric acid?

Answer 1

$C{r}_2{O_7}^{2-}+14H^{+}+6e^{-}\to 2C{r}^{3+}+7H_{2}O$

$2x+7(-2)=-2$ $x=+3$

$2x-14=-2$

$2x=12$

$x=+6$

Change in Oxidation state $=3-6=-3$