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

When a solution of a mixture having two inorganic salts was treated with freshly prepared ferrous sulphate in an acidic medium,a dark brown ring was formed,whereas on treatment with neutral $FeCl_3$,it gave a deep red colour which disappeared on boiling and a brown-red precipitate was formed. The mixture contains:

The phosphate radical reacts with ammonium molybdate to form a precipitate of which color?

Anion which can react with $dil. H_2SO_4$ is

Why is it necessary to use acetic acid and not sulphuric acid for acidification of sodium extract for testing sulphur by lead acetate test?

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