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When H2O2 is shaken with an acidified solution of K2Cr2O7 in presence of ether, the ethereal layer turns blue due to the formation of A. Cr2O3 B. CrO4 2? C. Cr2 4 SO 3 b g D. CrO5

When H2O2
is shaken with an acidified solution of K2Cr2O7
in presence of ether, the ethereal layer turns
blue due to the formation of
A. Cr2O3 B. CrO4
2? C. Cr2 4 SO 3
b g D. CrO5

Grade:

2 Answers

Arun
25757 Points
2 years ago
blue colour is obtained when hydrogen peroxide is added to dichromate or any other Cr(VI) compound. The deep blue colour is due to formation of CrO(O2)2.
Vikas TU
14149 Points
2 years ago
 
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.

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