In acidic medium, H2O2 changes Cr O to CrO5 which has two (–– O –– O –––) bonds. Oxidation state of Cr in CrO5 is (AIMPT 2014)

When H2O2 is added to an acidified solution of a dichromate, 2 2 7 Cr O , a deep blue coloured complex, chromic peroxide, CrO5 [or CrO(O2)2] is formed. 2 2 7 2 2 2 2 2 Chromicperoxide Cr O 2H 4H O 2CrO O 5H O -> This deep blue coloured complex has the following structure. Oxidation state of Cr in CrO5 is + 6 due to the presence of two peroxide linkage, which can be calculated as: In CrO(O2)2, let the oxidation state of Cr be x. x 1 4 2 0 x 6 0 x 6 39. The reaction of aqueous KMnO4 with H2O2 in acidic conditions gives (AIPMT 2014) (a) Mn4+ and O2 (b)