Question

a student heated a few crystals of copper sulphate in a dry boiling tube . 1)what will be the colour of the copper sulphate after heating? 2) will u notice water droplets in the boiling tube?3)where have these come from?'

Answer 1

1) After heating the colour of copper sulphate will be white.
2) Yes, water droplets will be seen inside the boiling tube
3) These water droplets come from the water molecules of crystallisation.

Originally the colour of copper sulphate crystals will be blue due to the presence of water of crystallisation. On heating, the water of crystallisation will be lost and colour of the anhydrous copper sulphate will be white.