`[X]+H_(2)SO_(4) to [Y]` a colourless gas with irritating smell, `[Y]+K_(2)Cr_(2)O_(7)+H_(2)SO_(4) to` green solution.
`[X]` and `[Y]` are respectively :

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

`SO_(2) and H_(2)S`, both being reducing agents, can turn acidified dichromate solution green. `SO_(2)` can be obtained by the action of acid upon sulphite, while `H_(2)S` is evolved by the action of acid upon sulphide. However, `SO_(2)` has a burning sulphur smell which is irritating`. H_(2)S` has rotten egg like smell.