Question

Potassium chloride is added to water and stirred. A salt solution is obtained, which is then boiled, leaving behind a residue.

1. Is the above change physical or chemical?
2. Name the residue which remains behind after the salt solution is boiled.
3. Is the change reversible or not reversible?
4. Are the composition and properties of the original substance altered?
5. Give a reason why the above experimentation would not be possible if calcium carbonate was taken in place of potassium chloride.

Answer 1

1. Physical change
2. White residue of potassium chloride.
3. Change is reversible.
4. No, the composition and properties are not altered.
5. When in place of KCl, we take calcium carbonate, the above experiment cannot be possible as no new substance with new properties is produced since CaCO₃ is insoluble in water. Boiling will also not work as CaCO₃ is in solid form in water.