Yes, the crystals of salts are really dry as the water molecules present in them dont act as water but instead give them a crystaline structure. Copper sulphate crystals which seem to be dry contain water of crystallisation. When we heat the crystals, this water is removed and the salt turns white.

Introduction:
Salt crystals are a common household item that is often used for cooking and preserving food. They are also used for other purposes such as de-icing roads and sidewalks. However, the question arises whether the crystals of salt are really dry or not. In this response, we will explain in detail whether salt crystals are dry or not.

What are salt crystals?
Salt crystals are formed by the gradual evaporation of saltwater. The saltwater is left to evaporate, leaving behind salt crystals. These crystals are then harvested and used for various purposes.

Why are salt crystals considered dry?
Salt crystals are considered dry because they do not contain any free water molecules. The water molecules that were present in the saltwater have evaporated, leaving behind only solid salt crystals. Therefore, the crystals of salt are considered to be dry.

Can salt crystals absorb moisture?
Although salt crystals are considered dry, they can absorb moisture from the air. This is because salt is hygroscopic, which means it has a tendency to attract moisture from the air. When exposed to humid air, salt crystals can absorb moisture and become damp.

Conclusion:
In conclusion, salt crystals are considered to be dry because they do not contain any free water molecules. However, they can absorb moisture from the air and become damp.