Acidified potassium dichromate is treate...

Acidified potassium dichromate is treated with hydrogen sulphide. In the reactiion, the oxidation number of chromium

Increases from `+ 3` to `+ 6`

decreases from `+ 6` to `+ 3`

Remains unchanged

Decreases from `+ 6` to `+ 2`

Text Solution

Verified by Experts

The correct Answer is:

Decrease from `+ 6 ` to `+ 3`.
`K_(2) Cr_(2) O_(7) + 4H_(2) SO_(4) rarr K_(2) SO_(4) + Cr_(2) (SO_(4))_(3) + 4 H_(2) O + 3O`
`[H_(2) S + [O] rarr S + H_(2) O] xx 3`
`bar(K_(2) overset(+6)Cr2O_(7) + 4H_(2) SO_(4) + 3 H_(2) S rarr K_(2) SO_(4) + overset(+3)Cr (SO_(4))_(3) + 7 H_(2) O + 3S)`

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Acidified potassium dichromate on reacting with a suplhite is reduced to

`CrO_(2) C1_(2)`

`CrO_(4)^(2-)`

`Cr^(3+)`

`Cr^(2+)`

Acidified potassium dichromate solution is decolourised by

Bleaching powder

White vitriol

Mohr's salt

Microcosmic salt

Acidified potassium permangate can't oxidize

`C_(2)O_(4)^(2-)`

`N_(2)H_(4)`

`SO_(4)^(2-)`

`S_(2)O_(3)^(2-)`