`[X] + dil.H_(2)SO_(4) to [Y] , ` colourless suffocating gas `[Y] + K_(2)Cr_(2)O_(7) + H_(2)SO_(4) to ` Green colouration of solution . Then [X] and [Y] are -

Options

A. `SO_(3)^(2-), SO_(2)`
B. `Cl^(-), HCl`
C. `S^(2-),H_(2)S`
D. `CO_(3)^(2-) , CO_(2)`

Answer

A

Explanation

`underset([X])SO_(3)^(2-)` + dil . `underset("[Y,colourless, suffocating gas]")(H_(2)SO_(4) to SO_(2)(g) 3SO_(2)(g) + K_(2)Cr_(2)O_(7)) + H_(2)SO_(4) Cr_(2) underset("(green)")((SO_(4))_(3)) + K_(2)SO_(4) + K_(2)SO_(4) + H_(2)O`