$A$ salt gives violet vapours when treated with concentrated $H_2SO_4$,it contains

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

Sodium sulphite on heating with dilute $HCl$ liberates a gas which

Neutral ferric chloride is added to the aqueous solution of acetate. $A$ blood-red colour is obtained; this is due to the formation of which compound?

$A$ salt,which on heating with conc. $H_2SO_4$ gives violet vapours,is

$A$ sodium salt on treatment with $MgCl_2$ gives white precipitate only on heating. The anion of the sodium salt is