NaClH2O

NaClH2O is not a discrete chemical compound with a fixed formula; in common usage it denotes sodium chloride dissolved in water, i.e., an aqueous solution of NaCl. In such a solution, NaCl dissociates into Na+ and Cl− ions that are solvated by water molecules. There is no stable solid hydrate of sodium chloride under ordinary conditions; NaCl·H2O as a crystalline compound is not known, and any water associated with solid NaCl at ambient conditions is typically a surface-adsorbed film rather than a true hydrate.

Properties of NaCl in water depend on concentration. As an electrolyte, NaCl increases the solution’s electrical conductivity in proportion to the number of dissociated ions, though deviations from ideal behavior occur at higher concentrations. The dissolution of NaCl in water is typically slightly endothermic. Colligative properties, such as boiling-point elevation and freezing-point depression, depend on the mole fraction of solute. Aqueous NaCl solutions are often near neutral in pH because neither Na+ nor Cl− appreciably hydrolyzes water.

Preparation and applications are straightforward: common salt (NaCl) is dissolved in water to produce NaClH2O. Such solutions are widely used in food seasoning and preservation, medicine, chemical synthesis, and industrial processes. Saturated solutions at room temperature can reach several moles of NaCl per liter.

Safety is generally favorable at typical concentrations; extremely concentrated solutions can irritate tissues or cause osmotic effects if ingested in large amounts. When referring to hydrated forms, NaCl·xH2O is distinct from NaCl(aq) and is not the usual state for sodium chloride in ordinary conditions.