21.Which sulphides are soluble only in aqua regia?

22.Sulphuric acid is not used for the preparation of original solution in the analysis of basic radicals because

23.The aqueous solution of which of the following reagent will give prussian blue coloured precipitate with an aqueous solution containing iorn (III) ions.

24.A one litre flask is full of brownbromine vapour. The intensity of brown colour of vapour will not decrease appreciably on adding to the flask some

25.Certain Inorganic salt gives yellow precipitate with silver nitrate. The precipitate dissolves in dilute nitric acid as well as in ammonium hydroxide. The solution contains