What are solutions?

Solutions are defined as stable mixtures of two or more substances where one substance (the solute) is dissolved in another (the solvent). This process results in a homogeneous mixture at the molecular level, meaning that the components are evenly distributed throughout the solution. In this context, the stability of the mixture is significant because it implies that the components do not separate over time, maintaining a consistent composition.

In practical applications like hair coloring, knowing how solutions work is crucial. For instance, when hair color is mixed with a developer, you are creating a solution that will effectively penetrate the hair shaft to achieve the desired color. The stability ensures that the mixture remains effective throughout the application process.

Other options describe scenarios that do not align with the definition of solutions. For instance, mixtures that cannot mix are considered immiscible and do not form solutions. Unstable chemical compounds would not maintain their composition over time and therefore cannot be classified as solutions. Lastly, solely gases mixed together do not encompass the broader category of solutions, which can involve solids, liquids, and gases. Thus, the characterization of solutions as stable mixtures of multiple substances is both clear and applicable in various contexts.