Question

how can a hydrated salt can be converted into anhydrous salt

Answer 1

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Often, a hydrated salt can beconverted 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.

Answer 2

an hydrated salt contains it water of crystallisation . when we heat hydrated salt ,it removes or drives it water molecules and thus formed anhydrous salt without any water of crystallisation

so with the heating process we convert hydrated salt into a anhydrous salt