What defines a solution in chemistry?

A solution in chemistry is defined as a homogeneous mixture that consists of two or more substances. This means that the components of the solution are uniformly distributed at a molecular or ionic level, resulting in a consistent composition throughout. For example, when salt is dissolved in water, the sodium and chloride ions disperse evenly within the water, creating a solution that has the same properties throughout.

The term "homogeneous" indicates that you cannot distinguish the various components of the solution with the naked eye or even under a microscope, as they blend seamlessly into one another. This characteristic differentiates solutions from other types of mixtures, such as suspensions and colloids, where the particles are not fully dissolved and can be seen or separated out.

By contrast, a solution is not merely a mixture of solid particles, which would suggest a heterogeneous combination where the components remain distinct. It also is not limited to specific interactions like those found in colloids or solely to pure substances dissolved in a gas, as solutions can involve a variety of combinations of solutes and solvents, including liquids, gases, and solids. Thus, the concept of a homogeneous mixture accurately encapsulates what a solution is in the context of chemistry.