An orange solid `(A)` on heating gave a green residue `(B)`, colourless gas `( C)` and water vapour. The dry gas `( C)` on passing over heated magnesium gave a white solid `(D).(D)` on reaction with water have a gas `( E)` which formed dense white fumes with `HCl`. Indentify `(A)` to `( E)` and give the reactions.

Explanation

(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))`