The gas librated , on heating a mixture of two salts with `NaOH` give sa reddish brown precipitate with an alkline solution of `K_(2)HgI_(4)` the aqeous solution of the mixture on treatment with `BaCI_(2)` gives awhite precipitate which is sparingly soluble with `K_(2)Cr_(2)O_(7)` and concentrated `H_(2)SO_(4)`red vapour of A are produced .The aqueous solution of the mixture gives a deep -blue colouration B with potassium ferrcyanide soluble identify the redicals in the gives mixture and write the balanced equation in the gives mixture and write the balanced equations for the formation of A and B

Explanation

`NH_(4^(*)),Fe^(2+),SO_(4^(2-)),CI^(-)`
Formation of a reddish brown ppt with alkaline `K_(2)Hgl_(4)` solution indicates the presence of radical ammonium `NH_(4^(+))` and the gas liberated in ammonia. The reactions are as:
`NH_(4)^(+)OH^(-)toNH_(3)+H_(2)O`
`K_(2)Hgl_(4)to2KI+Hgl_(2)`
`Hgl_(2)+2NH_(3)toHg(NH_(2))l+NH_(4)l`
`Hg(NH_(2))l+HgltoNH_(2)Hg_(2)ł_(3)`
On treatment with Bacla, a white ppt is formed which indicates the presence of sulphate anion `(SO_(4)^(2-))` sparingly soluble in conc. HCI.
With `K_(2)Cr_(2)O_(7)` and conc. `H_(2)SO_(4)` red vapours are evolved which indicates the presence of chloride ion `(Cl^(-))`. The reaction is as:
`K_(2)Cr_(2)O_(7)+4Cl^(-)+underset(conc.)(6H_(2)SO_(4))tounderset(A)(2CrO_(2)Cl_(2))+2KHSO_(4)+4HSO_(4)^(-)+3H_(2)O`
On treatment with potassium ferricyanide indicates the presence of ferrous ions.
`[Fe(CN)_(6)]^(3-)toFe^(3+)+[Fe(CN)_(6)]^(4)`
`4Fe^(3+)+3K_(4)[Fe(CN)_(6)]toFe_(4)underset(deep blue)([Fe(CN)_(6)]_(3))+12K^(+)`