How is a solution defined in the context of chemistry?

In chemistry, a solution is defined as a homogeneous mixture, which means that the components of the mixture are uniformly distributed at the molecular level. This uniformity is key to identifying a solution, as it exhibits a consistent composition throughout, regardless of the amount sampled.

In a solution, one substance (the solute) is dissolved in another (the solvent), and the resulting mixture has properties that are consistent throughout. For example, when table salt is dissolved in water, the salt dissociates into its individual ions and becomes evenly distributed within the water, forming a clear, uniform solution that appears the same regardless of where in the mixture one samples it.

This characteristic distinguishes solutions from heterogeneous mixtures, where the individual components can be visually distinguished and are not uniformly distributed. Additionally, solutions are not classified as solid substances or pure elements; rather, they can exist in any state of matter (solid, liquid, or gas), as long as they maintain that homogeneous mixture quality.