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 $(X)$?

Which reagent below would enable you to remove sulphate ions from a solution containing both sulphate and chloride ions?

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

To a solution of a colourless sodium salt, a solution of lead nitrate was added to form a white precipitate which dissolves in warm water and reprecipitates on cooling. Which of the following acid radicals is present in the salt?

$A$ mixture is heated with dilute $H_2SO_4$ and the lead acetate paper turns black due to the evolved gases. The mixture contains:

Choose the correct matching:-

Column-$I$	Column-$II$
$(P) NaBr + \text{conc. } H_2SO_4 \rightarrow$	$(A) \text{Colourless gas}$
$(Q) Na_2S + \text{dil. } HCl \rightarrow$	$(B) \text{Brown colour}$
$(R) NaNO_2 + \text{dil. } HCl \rightarrow$	$(C) \text{Rotten smell}$
$(S) NaNO_3 + \text{conc. } H_2SO_4 \rightarrow$	$(D) \text{Paramagnetic}$