Why H2O2 reacts with K2Cr2O7 to give blue colour ?........

HELLO THERE!

 

Let’s check out the reaction of hydrogen peroxide with acidified Potassium dichromate:

 

K₂Cr₂O₇ + H₂SO₄ + 4H₂O₂ ------> K₂SO₄ + 2CrO₅ + 5H₂O

 

The formation of Chromium Pentaoxide leads to the formation of blue colour from orange (as potassium dichromate is orange in colour). Chromium Pentaoxide is blue in colour, so we get a blue colour after the reaction.

 

In the reaction, Hydrogen peroxide acts as an oxidizing agent, because it itself gets reduced, and its oxidation number changes to -2 from -1.

 

THANKS!