Q. When hydrogen peroxide is added to acidified potassium dichromate, a blue colour is produced due to formation of
A) ${CrO}_{3}$
B) ${Cr}_{2}O_{3}$
C) ${CrO}_{5}$
D) ${CrO}_{4}^{2 -}$
Explanation
(c)
Acidified potassium dichromate is oxidized to unstable blue chromium peroxide, which is soluble in ether and produces blue coloured solution.
$K_{2}{Cr}_{2}O_{7} + H_{2}{SO}_{4} + 4H_{2}O_{2}\ \longrightarrow 2{CrO}_{5} + K_{2}{SO}_{4} + 5H_{2}O$
blue colour
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.