$A$ mixture when heated with conc. $H_2SO_4$ and $MnO_2$ produces brown fumes due to the presence of:

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

When a few drops of $KMnO_4$ are added to an acidic solution of an anion,which of the following,if present,will $NOT$ decolorize $KMnO_4$?

$A$ white precipitate was formed when $BaCl_{2}$ was added to the water extract of an inorganic salt. Further,a gas $X$ with a characteristic odour was released when the formed white precipitate was dissolved in dilute $HCl$. The anion present in the inorganic salt is ..... .

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

White heavy precipitates are formed when $BaCl_2$ is added to a clear solution of compound $A$. Precipitates are insoluble in dilute $HCl$. Then,the compound $A$ is