The Chromyl chloride test is performed for the confirmation of the presence of which of the following in a mixture?

The incorrect statement in respect of the chromyl chloride test is:

When $BaCl_{2}$ is added to an aqueous salt solution,a white precipitate is obtained. The anion among $CO_{3}^{2-}$,$SO_{3}^{2-}$,and $SO_{4}^{2-}$ that was present in the solution can be

During the detection of an acidic radical present in a salt,a student obtains a pale yellow precipitate that is soluble with difficulty in $NH_4OH$ solution when the sodium carbonate extract is first acidified with dil. $HNO_3$ and then $AgNO_3$ solution is added. This indicates the presence of:

$[X] + H_2SO_4 \rightarrow [Y]$ (a colorless gas with a pungent smell). $[Y] + K_2Cr_2O_7 + H_2SO_4 \rightarrow$ green solution. What are $[X]$ and $[Y]$?

$AgNO_3$ gives a red precipitate with: