A light bluish-green crystalline compound responds to the following tests: (i). Its aqueous solution gives a brown precipitate on reaction with alkaline K_2[HgI_4] solution. (ii). Its aqueous solution gives a blue colour with K_3[Fe(CN)_6] solution. (iii). Its solution in hydrochloric acid gives a white precipitate with BaCl_2 solution. Identify the ions present and suggest the formula of the compound.

A light bluish-green crystalline compound responds to the following te

1.	A light bluish-green crystalline compound responds to the following tests: (i). Its aqueous solution gives a brown precipitate on reaction with alkaline K_2[HgI_4] solution. (ii). Its aqueous solution gives a blue colour with K_3[Fe(CN)_6] solution. (iii). Its solution in hydrochloric acid gives a white precipitate with BaCl_2 solution. Identify the ions present and suggest the formula of the compound.
Answer» Solution :Its aqueous solution gives a brown precipitate or COLOURATION with alkaline `K_2[HgI_4]` solution. This suggests ammonium IONS. Its aqueous SOLUTIONS gives a blue colour with `K_2[Fe(CN)_6]` solution. This suggests ferrous ions. Its solution in hydrochloric acid gives a white precipitate with `BaCl_2` solution. This suggest sulphate ions. The formula of the compound can be `FeSO_4(NH_4)_2SO_4.6H_2O` (MOHR's SALT.)