A mixture of two salts was treated as follows.
(i)The mixture was heated with precipitated `MnO_(2)` and concentrated `H_(2)SO_(4)` when a yellowish green gas was liberated.
(ii)The mixture on heating with `NaOH` solution gave a gas which turned red litmus blue.
(iii)Its solution in water gave red colouration with dimethylglyoxime in alkaline solution and white precipitate with `K_(4)[Fe(CN)_(6)]` in absence of air.
(iv)The mixture was boiled with `KOH` and the liberated gas was bubbled through an alkaline solution of `K_(2)HgI_(4)` to give a brown precipitate. Identify the ions present in the mixture.

Answer

The given unknown mixture contains `NH_(4)^(+),Fe^(2+)` and `Cl^(-)` ions or `NH_(4)Cl` and `FeCl_(2)`