## PASSAGE 24
- When an aqueous solution of a colourless mixture of two salts is treated with a drop of chlorine water, the solution becomes brown. Some chloroform is added to the brown solution and the resulting mixture is shaken well. The chloroform layer becomes violet.
- When chlorine water is again added dropwise to the above mixture, the chloroform layer becomes colourless.
- On being heated with solid K2Cr2O7 and concentrated H2SO4 , the solid mixture gives vapours of a dark colour which form a yellow solution with aqueous NaOH . On acidification with acetic acid followed by treatment with lead acetate, the yellow solution gives a yellow precipitate.
- When boiled with an NaOH solution, the mixture gives a gas that produces thick white fumes with HCl vapours and turns Nessler's reagent brown. The mixture does not respond to any other test for cations.
- The mixture, on being heated, gets completely sublimed.
The original mixture contains:
(1) NH4Cl and NH4Br
(2) NH4Br and NH4I
(3) NH4Cl and NH4I
(4) NH4Cl and NH4NO3