When H2O2is added to ice cold solution of acidified potassium dichroma...
When H
2O
2 is added acidified potassium dichromate in ether solution, potassium dichromate is oxidised to blue peroxide of chromium (CrO
5) which is soluble in ether and produces blue coloured solution.
K
2Cr
2O
7 + H
2SO
4 + 4H
2O
2
2CrO
5 + K
2SO
4 + 5H
2O
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When H2O2is added to ice cold solution of acidified potassium dichroma...
Explanation:
When hydrogen peroxide (H2O2) is added to an ice-cold solution of acidified potassium dichromate in ether, several reactions take place. Let's analyze each option to determine the correct answer:
a) A blue colour is obtained in ether due to the formation of Cr2(SO4)3:
This option suggests the formation of chromium(III) sulfate (Cr2(SO4)3). However, when acidified potassium dichromate reacts with hydrogen peroxide, the oxidation state of chromium changes from +6 to +5. Therefore, the formation of Cr2(SO4)3 is not possible in this reaction.
b) A blue colour is obtained in ether due to the formation of CrO5:
This option suggests the formation of chromium(V) oxide (CrO5). When acidified potassium dichromate reacts with hydrogen peroxide, the chromium(V) intermediate CrO5 is formed. This intermediate is responsible for the blue color observed in the ether layer.
c) A blue colour is obtained in ether due to the formation of CrO3:
This option suggests the formation of chromium(VI) oxide (CrO3). However, in the reaction between acidified potassium dichromate and hydrogen peroxide, the oxidation state of chromium changes from +6 to +5. Therefore, the formation of CrO3 is not possible in this reaction.
d) Chromyl chloride is formed:
Chromyl chloride (CrO2Cl2) is not formed in the reaction between acidified potassium dichromate and hydrogen peroxide. Chromyl chloride is formed when a chloride salt reacts with acidified potassium dichromate and concentrated sulfuric acid. It is not a product of the given reaction.
Therefore, the correct answer is option 'b' - A blue color is obtained in ether due to the formation of CrO5.