Question

Why is ammonium hydroxide used in qualitative analysis? Give two equations to justify your answer.

Answer 1

When correct amount of ammonium hydroxide is added drop wise to solutions of the metallic salts, ppts. (coloured generally) are formed. They help us to identify their metal ions.
Two equations:
FeSO₄ + 2NH₄OH → (NH₄).₂SO₄ + Fe (OH)₂
(Green) (Dirty green)
shows the presence of Fe⁺² ion.
FeCl₃ + 3NH₄OH → 3NH₄Cl + Fe (OH)₃
(Brown) (Reddish brown)
shows the presence of Fe⁺³ ion.