In acidic medium, `H_(2)O_(2)` changes `Cr_(2)O_(7)^(2-)` to `CrO_(5)` which has two `(-O-O-)` bonds. Oxidation state of Cr in `CrO_(5)` is

Options

A. `+5`
B. `+3`
C. `+6`
D. `-10`

Answer

C

Explanation

When `H_(2)O_(2)` is added to an acidified solution of a dichromate `Cr_(2)O_(7)^(2-)`, a deep blue coloured complete, chromatic peroxide `CrO_(5)` (or `CrO(O_(2))_(2))` is formed
`Cr_(2)O_(7)^(2-) + H^(-) + 4H_(2)O to 2CrO(O_(2))_(2)`
Blue coloured complex + `5H_(2)O`
The deep blue coloured complex has the following strucure

Oxidation state of Cr in `CrO_(5)` us `+6` due to the presence of two peroxide linkages which can be calculate as
`underset("For" Cr)(Fe)+underset("For"0-0)(-1) xx 4+1 underset("For"0) xx (-2)`
`x-6=0`
`x=+6`