In acidic medium, H₂O₂ changes Cr₂O₇²⁻ to CrO₅ which has two (–O–O–) bonds. Oxidation state of Cr in CrO₅ is:

6 2014 AIPMT Redox ReactionsOxidation Number Medium
In acidic medium, $H_2O_2$ changes $Cr_2O_7^{2-}$ to $CrO_5$ which has two (–O–O–) bonds. Oxidation state of Cr in $CrO_5$ is:
A +5
B +3
C +6
D −10

Detailed Solution

$CrO_5$ has two peroxy linkages: four O atoms are in the −1 state and one is in the −2 state.

$x + 4(-1) + (-2) = 0 \Rightarrow x = +6$

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