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

The brown ring test is used to detect the presence of which of the following ions?

When $BaCl_2$ is added to a clear solution of compound $(X)$,a heavy white precipitate is formed,which is insoluble in dilute $HCl$. What is compound $(X)$?

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

How do you account for the following observations?
$(a)$ Though alkaline potassium permanganate and acidic potassium permanganate both are used as oxidants,yet in the manufacture of benzoic acid from toluene,we use alcoholic potassium permanganate as an oxidant. Why? Write a balanced redox equation for the reaction.
$(b)$ When concentrated sulphuric acid is added to an inorganic mixture containing chloride,we get a colourless pungent-smelling gas $HCl$,but if the mixture contains bromide,then we get red vapours of bromine. Why?

When $BaCl_2$ is added to a clear solution of a compound $(X)$,a heavy white precipitate is formed which does not dissolve in $dil. HCl$. What is the compound $(X)$?