ICSE Class 10 Answered

1.  It has a sharp characteristic odour.
2.  It turns moist red litmus blue, methyl orange from orange to yellow and phenolphthalein from colourless to pink.
3.  It produces dense white fumes with conc. HCl.

            NH₃ +HCl   → NH₄Cl

      4.  It forms a blue precipitate with copper sulphate and then dissolves it to form a deep coloured solution in excess of ammonia.

            CuSO₄ + 2NH₄OH → (NH₄)₂SO₄ +Cu (OH)₂

      5.  Colourless Nessler’s reagent turns pale brown on passage of excess ammonia.