What would you observe when :
(a) A saturated solution of potassium nitrate prepared at `60^(@)C` is allowed to cool to room temperature ?
(b) A mixture of iron filings and sulphur is heated strongly ?
(c ) A colloidal solution of starch is passed through an ordinary filter paper ?

Explanation

(a) Crystals of potassium nitrate which are needle shaped would slowly appear at the bottom of the container which may be a china dish or a beaker.
(b) A greyish-black mass passes formed.
(c ) The solution passes through the ordinary filter paper without leaving any residue.