Question

On shaking $H_2{O}_2$ with acidified potassium dichromate and ether, the ethereal layer becomes:

• A. Green
• B. Red
• C. Blue
• D. Black

Answer 1

The correct option is C Blue

The blue colouration is due to the formation of $Cr{O}_5$.

$K_{2}C{r}_2{O}_7+H_{2}S{O}_4+4H_2{O}_2\to K_{2}S{O}_4+2Cr\underset{Blue}{O_5}+5H_{2}O$