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)