A substance on treatment with dil. `H_2 SO_4` liberates a colourless gas which produces (i) tubidity will baryta water and (ii) turns acidified dichromate solution green. The reaction indicates the presence of

Options

A. `C_(2)O_(3)^(2-)`
B. `S^(2-)`
C. `SO_(3)^(2-)`
D. `NO_(2)^(-)`

Explanation

`SO_(3)^(2-)` reacts with dil. `H_(2)SO_(4)` to evolve `SO_(2)` which gives turbidity with baryta water , an aqueous solution of `Ba(OH)_(2)` and turns acidified dichromate solution green on its reducrtion to `Cr^(3+)`.