Question

how can anhydrous salts regain their colour ​

Answer 1

Answer:

When water is then added to the anhydrous compound, it turns back into the pentahydrate form, regaining its blue color, and is known as blue vitriol. ... Iron reacts producing iron(II) sulfate and copper precipitates.

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Answer 2

ANSWER :-

Often, a hydrated salt can be converted into an anhydrous salt (one without water) by strong heating to drive off the water molecules. The mass of the hydrate will differ from the mass of the anhydrous salt by the mass of water that was removed during heating.On heating hydrated salt lose their water of crystalization as a resulted crystals lose theri shape and colour and changes to a powdered substance.