Question

Is there such case with a salt solution where hydrated salt version would not occur as the residue after evaporation, or vice versa with the anhydrous version?

Answer 1

The residue left after the evaporation of a salt solution could be hydrated or anhydrous, depending on the specific salt, the conditions of evaporation, and other factors like the temperature and presence of other ions.

Step-by-step explanation:

Yes, there are cases where after the evaporation of a salt solution, the residue may not be a hydrated salt, and conversely, instances where an anhydrous version of the salt won't occur. This can depend on several factors, including the nature of the salt, the temperature, and the presence of other ions.

When a salt solution is evaporated, the process typically leads to recrystallization where the solute returns to the solid state. In the case of sodium chloride (NaCl), for instance, evaporation of its aqueous solution typically yields an anhydrous crystalline residue. However, some salts can form hydrated salts as a residue, where water molecules are integrated into the crystal structure of the solid, depending on the conditions.

For salts that form such hydrated crystals, ongoing hydration helps stabilize the ions in the solution, preventing them from recombining into a solid unhydrated salt. Different salts have different tendencies to form these hydrated crystals. Factors like solubility, temperature, and the presence of other ions in the solution can influence whether a hydrated or anhydrous salt remains after evaporation.