`K_(2)Cr_(2)O_(7)//H^(+)` changes to green by

Options

A. `Fe^(2+)`
B. `SO_(2)`
C. Both (a) and (b)
D. None of these

Answer

C

Explanation

`Cr_(2)O_(7)^(2-)+SO_(2)+H^(+)rarrunderset("green")(2Cr^(3+))SO_(4)^(2-)+Fe^(2+)+H^(+)rarrunderset("Green")(Cr^(3+))+Fe^(3+)`
`SO_(2)and Fe^(2+) "both reduce"Cr_(2)O_(7)^(2-)"to"Cr^(3+)("green").`