dilutabilitysolubility

D ilutability and solubility are related concepts in solution chemistry that describe how a substance interacts with a solvent. Solubility is the maximum amount of solute that can dissolve in a given amount of solvent at a specified temperature and pressure to form a stable, homogeneous solution. It is typically expressed in units such as grams of solute per 100 grams of solvent, molarity (moles per liter), or grams per liter, and it often depends strongly on temperature and, for gases, on pressure. Substances can be highly soluble, sparingly soluble, or insoluble under particular conditions.

Dilutability refers to how readily a solution can be diluted by adding more solvent, thereby reducing the concentration of dissolved solute. Dilutability is constrained by solubility: if the current concentration is well below the solubility limit, dilution simply reduces concentration with little risk of precipitation. If the solution is near saturation, adding solvent can cause undissolved solute to re-enter solution only if the temperature remains the same and the solubility limit allows it; alternatively, dilution can reveal impurities or trigger precipitation if conditions change.

In practice, dilutability is often quantified by dilution equations such as the C1V1 = C2V2 relationship used in serial dilutions, where the final concentration C2 is achieved by combining initial concentration C1 with volumes V1 and V2. Temperature, pH, solvent composition, and the presence of other ions or complexing agents can alter both solubility and the ease of dilution, especially for solutions near saturation or those subject to chemical reactions during dilution.

Common examples include dissolving table salt or sugar in water, which are easily diluted, in contrast to solutions of sparingly soluble compounds that require larger solvent volumes or elevated temperatures to maintain dissolution.