2NaClaq

2NaCl(aq) denotes two moles of sodium chloride dissolved in water, i.e., two units of table salt present in an aqueous solution. The “aq” tag indicates that the species are in the aqueous phase. In typical notation, sodium chloride dissolves in water by dissociation into ions: NaCl(aq) → Na+(aq) + Cl−(aq). Therefore, 2NaCl(aq) corresponds to 2 Na+(aq) and 2 Cl−(aq) in solution.

Sodium chloride is highly soluble in water. At room temperature, its solubility is about 359 g per liter of water, roughly 6.1 moles per liter. The dissolution is mildly endothermic, with a small positive enthalpy of solution, and the resulting solution conducts electricity due to the presence of mobile Na+ and Cl− ions. In general, the more NaCl that is dissolved, the higher the ionic strength and electrical conductivity of the solution, up to the limits of solubility.

In practical contexts, 2NaCl(aq) is primarily a stoichiometric descriptor rather than a distinct chemical entity. It is used in balanced equations and calculations to indicate two moles of dissolved sodium chloride. Common applications include laboratory titrations, brine chemistry, and formulations such as physiological saline, where about 0.9% w/v NaCl is used. Safety considerations for typical concentrations are low, though very high salt concentrations can impose osmotic stress on biological systems.