Effervescent waters all contain some gas, usually carbonic acid gas in solution, and they merely give up or set free a part of it when placed in open vessels.
Sulfur water
Sulfur water contains a compound of hydrogen and sulfur, called hydrogen sulfid or sulfureted hydrogen, which we will refer to in its order later in this lesson.
Distilled water
Water may be purified by means of distillation. This consists in boiling the water and condensing the vapor by passing it through a tube which is kept cool by surrounding it with cold water. By means of distillation most substances in solution in water can be eliminated. Substances, however, which evaporate like water, will, of course, pass off with the water vapor. Aboard ship salt water is distilled and thus made fit for drinking. In chemical laboratories ordinary water is distilled in order to purify it for chemical work.
USES OF WATER IN CHEMISTRY
Action of water in physiological chemistry
Water is termed by the chemist a stable compound. This means that it is difficult to get it to act chemically. Being thus inactive chemically, we find that water does not combine with most substances. There are exceptions to this, however, especially in physiological chemistry, an instance being that starch combines with water when it is changed to sugar in the process of digestion.
Water as a solvent