Substance (A) is a colourless pungent smelling gas of vapour density 8.5. It turned Nessler's reagent brown. (A) on oxidation at high temperature with platinum catalyst gave a colourless gas (B), which readily turned brown in air, forming a gas (C). (B) and (C) were condensed together to give substance (D), which reacted with water to form an acid (E). When (E) was heated with a solution of NH_(4)Cl, a stable gas (F) was evolved. (F) did not support combustion, but magnesium continued to burn in it. Itentify substances (A) to (F) and explain all the reactions involved.

Substance (A) is a colourless pungent smelling gas of vapour density 8

1.	Substance (A) is a colourless pungent smelling gas of vapour density 8.5. It turned Nessler's reagent brown. (A) on oxidation at high temperature with platinum catalyst gave a colourless gas (B), which readily turned brown in air, forming a gas (C). (B) and (C) were condensed together to give substance (D), which reacted with water to form an acid (E). When (E) was heated with a solution of NH_(4)Cl, a stable gas (F) was evolved. (F) did not support combustion, but magnesium continued to burn in it. Itentify substances (A) to (F) and explain all the reactions involved.
Answer» Solution :(i) `underset(("A"))underset("Ammonia")(NH_(3)) + underset("Nessler's reagent")(2K_(2)Hgl_(4)) + 3 KOH rarr underset(("Brown ppt."))underset("Iodide of Million's base")(H_(2)N.Hg.O.HGL) + 7 KI + 2 H_(2)O` (ii) `underset("Ammonia (A)")(4 NH_(3)) + 5 O_(2) overset("Pt. Heat")rarr underset("Nitric OXIDE (B)")(4 NO) + 6 H_(2)O` (iii) `2 NO + O_(2) rarr underset(("Brown"))underset("Nitrogen dioxide (C)")(2 NO_(2))` (iv) `NO + NO_(2) overset("Condensed")rarr underset("Dinitrogen trioxide (D)")(N_(2)O_(3))` (v) `N_(2)O_(3) + H_(2) O rarr underset("Nitrous acid (E)")(2 HNO_(2))` (VI) `HNO_(2) + NH_(4)Cl rarr underset("Nitrogen (F)")(N_(2)) + 2 H_(2)O + HCl` (vii) `underset("Magnesium")(Mg) + N_(2) overset("Heat")rarr underset("Magnesium nitride")(Mg_(3)N_(2))`