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.

Answer

(A)`(NH_(4))_(2)Cr_(2)O_(7)`; (B)`Cr_(2)O_(3)`; ( C)`N_(2)`; (D)`Mg_(3)N_(2)` ; (E)`NH_(3)`

Explanation

Assume compound (A),`(NH_(4)))_(2)Cr_(2)O_(7)`
Reaction : `underset((A))((NH_(4))_(2)Cr_(2)O_(7))overset(Delta)tounderset((C))N_(2)+underset(Green(B))(Cr_(2)O_(3))+4H_(2)O , N_(2)+3Mg overset(Delta)to underset((D))(Mg_(3)) N_(2)`
`underset((D))(Mg_(3))N_(2)+6H_(2)O to 3Mg(OH)_(2)+underset((E))(2NH_(3)) , underset((E))(NH_(3))+HCltounderset(("White fumes"))(NH_(4)Cl)`