mischbare

Mischbare is a term used to describe liquids that are mutually soluble, forming a single homogeneous phase in all proportions at a given temperature. In English, the corresponding term is miscible. When two liquids are mischbare, each dissolves completely in the other, so no phase separation occurs upon mixing.

Thermodynamics underpins miscibility. The tendency of liquids to mix is described by the Gibbs free energy of mixing, ΔG_mix. If ΔG_mix is negative for all compositions at a given temperature, the liquids are miscible across the full range of mixtures. In ideal solutions, Raoult's law provides a simple framework, but real systems often show deviations caused by molecular interactions. Temperature can alter miscibility: some liquid pairs are miscible only within certain temperature windows, a phenomenon described by upper critical solution temperature (UCST) or lower critical solution temperature (LCST).

Common examples illustrate the concept. Water and ethanol are miscible in all proportions. Water and acetone are miscible as well. Nonpolar hydrocarbons such as hexane and toluene are miscible with each other. By contrast, water and oil are typically immiscible, forming two distinct liquid phases.

Mischbarkeit has broad practical importance. It guides solvent selection in chemical synthesis, pharmaceutical formulations, paints and coatings, and polymer blending. It also affects extraction processes and the design of formulations where uniform mixing is essential. Related terms include immiscible and partially miscible, which describe systems that do not mix completely or only do so within limited ranges of composition or temperature.