Question:
What would you observe when
(a) a saturated solution of potassium chloride prepared at $60^{\circ} \mathrm{C}$ is allowed to cool to room temperature.
(b) an aqueous sugar solution is heated to dryness
(c) a mixture of iron filings and sulphur powder is heated strongly.
Solution:
(a) Upon cooling, crystals of potassium chloride would separate.
(b) Initially, entire water slowly gets removed. Upon further heating, sugar gets charred and burning smell will be noticed.
(c) Iron sulphide is formed as a greyish black residue.