Question

The gas liberated on heating a mixture of two salts with NaOH gives a reddish brown precipitate with an alkaline solution of K₂Hgl₄. salts with NaOH gives a reddish brown precipitate with an alkaline solution of K₂Hgl₄. The aqueous solution of the mixture on treatment with BaCl₂ gives a white precipitate which is sparingly soluble in concentrated HCl. On heating the mixture with K₂Cr₂O₇ and conc. H₂SO₄, red vapours (A) are produced. The aqueous solution of the mixture gives a deep blue colouration (B) with K₃Fe(CN)₆] solution. Identify the radicals in the given mixture and write the balanced equations for the formation of (A) and (B).

Answer 1

i) The gas which is liberated on heating the mixture with NaOH gives red ppt. with K₂Hgl₄ so gas is NH₃ and mixture contains NH+4 ion. 

ii) Mixture on heating with K₂ Cr₂ O₇ and H₂ SO₄ gives red vapours of CrO₂ Cl₂ so mixture contains Cl^– ions.

iii) Aqueous solution of mixture gives blue colour with K₃[Fe(CN)₆ ] and thus, it contains Fe⁺² ion. 

iv) Thus mixtures has NH⁺₄, Fe⁺²,SO^-2₄,Cl^- Reaction: