A mixture of two salt was treated as follows :
i. The mixture was heated with magnanese dioxide and concentrated sulphuric acid , when a yellowish -green gas was liberated.
ii. The mixture on heating with sodium hydroxide solution gave a gas which turned red litmus blue
iii. Its solution in water gave a blue precipitate with potassium ferricyanide and red colourtion with ammonium thiocynate
iv. The mixture was boiled with potassium hydroxide and the librated gas was bubbled through an alkline solution of `K_(2)HgI_(4)` to give a brown precipitate identify the two salts gives ionic equation for the reaction involved in the tests (i) , (ii) and (iii).

Answer

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