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

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 $(X)$?

Choose the correct matching $:-$

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

Which one of the following anions is not easily removed from aqueous solutions by precipitation?

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?

Which of the following anions cannot be tested by $dil. H_2SO_4$?