A pale yellow substance `(A)` when heated with `conc. HNO_3` evolves a brown coloured gas `(B)`. The substance `(A)` also dissolves in sodium sulphite solution on heating. A clear solution `(C)` is formed which on acidification gives a turbid solution and a pungent smelled gas `(D)` which is formed by the substance `(A)` in air. The solution `(C)` decolourises iodine solution, Identify `(A)` to `(D)`.

(a). A powdered substance (A) on treatment with fusion mixture gives a green coloured compound (B). (b). The solution of (B) The solution of (B) in boiling water on acidification with dilute H_2SO_4 gives a pink coloured compound (C).

NaNO_(3) on heating with sodium hydroxide solution and zinc liberates a gas which is also obtained by :

When compound (A) is treated with conc. H_(2)SO_(4) , a reddish brown colour gas (B) is evolved. To this solution, a solution of (C ) is added slowly from the side of the test tube, a blue ring is obtained at the junction of two layers due to formation of (D). Compound (D) has formula :

Magnesium on heating in air gives (A) and (B) . On reaction with water (B) gives a colourless gas (C ).(C ) when passed through CuSO_(4) solution, gives a blue coloured solution (D) . Identify (C ) and (D) .

A sulphide ore (A) on roasting leaves a residue (B). (B) on heating with chlorine gives (C), soluble in water, addition of excess potassium iodide to a solution of (C) gives a solution (D). A brown precipitate (E) is formed when a solution of ammonium sulphate is added to an alkaline solution of (D). Identify (A) to (E).

A sulphide ore (A) on roasting leaves a residue (B) . (B) on heating with chlorine gives (C ) , sulphide in water, addition of excess potassium iodide to a solution of (C ) gives a solution (D) A brown precipitate (E) is formed when a solution of ammonium sulphate is added to an alkaline a solution of (D) . Identify (A) to (E) .

An aqueous solution of a substance gives a white percipitate on treatment with dil HCl , which dissole on heating. On passing H_(2)S in hot acidic solution a black percipitate is formed. The substance is:

A gaseous substance dissolve in water giving a pale blue solution which decolouises KMnO_(4) and oxidises Kl to l_(2) in acidic medium :

Identify the substance R based on the information given below: The pale green solid R turns reddish brown on heating. Its aqueous solution gives a white precipitate with barium chloride solution. The precipitate is insoluble in mineral acids.

A white amorphous powder (A) when heated gives a colourless gas (B), which turns lime water milky and the residue (C) which is yellow when hot but white when cold. The residue (C) dissolves in dilute HCl and the resulting solution gives a white precipitate on addition of potassium ferrocyanide solution. (A) dissolves in dilute HCl with the evolution of a gas which is identical in all respects with (B). The solution of (A) as obtained above gives a white precipitate (D) on addition of excess of NH_(4)OH and on passing H_(2)S . Another portion of this solution gives initially a white precipitate (E) on addition of NaOH which dissolves in excess of it. Compounds (A) to (E) are identified as: