Would High Heat Cause Salt to Evaporate From a Saltwater Pool?
- Salt is an ionic compound, meaning the sodium has lost an electron to the chlorine, so it has a positive charge and the chlorine has a negative charge. The two ions are strongly attracted to each other, and this force holds them together tightly. When the salt dissolves in water, the interactions between the ions are replaced by interactions between ions and water molecules. As the temperature of the water rises, the water molecules move more rapidly, and some of them move quickly enough they escape, so the water starts to evaporate.
- While the water evaporates as the temperature rises, the salt does not; it remains behind. The attraction between the sodium and chloride ions is strong enough that an extremely high temperature would be required to vaporize the salt. The boiling point for sodium chloride is 2,575 degrees Fahrenheit--so unless the temperature of your saltwater pool is approaching that value, evaporation of the salt crystals shouldn't be a problem.
- While the salt itself doesn't evaporate, it does have an effect on how quickly the water evaporates. The interactions between water molecules and salt ions make it more difficult for the water molecules to break free and escape. Water evaporates a little more slowly, and its boiling point rises as the concentration of dissolved salt increases.