State the observation:
1.when crystals of copper sulphate are heated in a test tube
2.Ammonium sulphate is heated with NaOH and the gas liberated is bubble into methyl orange soln.
3.Ammonia gas is passed through copper nitrate solution.

Dear student,

1. Copper sulphate crystal (CuSO₄.5H₂O ) when heated in a test tube, it loses its water of crystallistion and changes its colour from blue to white.

2. Ammonium sulphate reacts with NaOH to form sodium sulphate, ammonia gas and water.
       (NH₄)₂SO₄ + 2NaOH $\to$ Na₂SO₄ + 2NH₃ + 2H₂O
Ammonia in water forms ammonium hydroxide( NH₄OH), which is basic in nature.
             NH₃ + H₂O  $\to$ NH₄OH
This changes the colour of methyl orange indicator from orange to yellow.

3. The blue colour of the copper(II) becomes more intense( or deep blue)  on additon of ammonia gas due to formation of a complex compound.
                 Cu²⁺ (aq) + 4 NH₃(aq)   $\to$ [Cu(NH₃)₄] ²⁺(aq) 
                   blue                                      deep blue
 Regards