Question

Action of heat on blue vitriol is a physical as well as chemical change.justify.

Answer 1

physical change - blue colour which gets escaped during heating can be reobtained by adding a few drops of water .

chemical change - when we heat it continuously for a long time then CuSO4 gets decopmosed.
CuSO4 -- CU+SO2+O2

Answer 2

Justification:

Blue Vitriol is hydrated Copper Sulphate. When blue vitriol is heated, it undergoes a physical change. This physical change is evident from the fact that we get white powder on heating hydrated copper sulphate. This happens because the water present in blue vitriol vaporises and what is left is an anhydrous element.

Now, when a drop of water is added to this “White Powder”, it changes back to blue colour. When heated, the hydrated copper sulphate decomposes to give oxides of copper and sulphur. On cooling these oxides, however, blue vitriol cannot be obtained as the reaction cannot be reversed and therefore this change is a chemical change.