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

Options

A. Increases from `+3` to `+6`
B. Decrease from `+6` to `+3`
C. Remains unchanged
D. Decreases from `+6`to `+2`

Answer

B

Explanation

Decreases from `+6` to `+3.`
`({:(K_(2) Cr_(2) O_(7) + 4H_(2)SO_(4) to K_(3) SO_(4)+Cr_(2) (SO_(4))_(3)+ 4H_(2)O+ 3O),([H_(2)S+[O] to S+ H_(2)O]xx3):})/(K_(2) overset(+6)(Cr_(2))O_(7)+4H_(2) SO_(4)+4H_(2) S to K_(2)SO_(4) +overset(+3)Cr_(2)(SO_(4))_(3)+7H_(2)O+3S)`