A solution, which is often abbreviated as "soln," is defined as a homogeneous mixture containing one solvent and one or more solutes that do not react with one another. Recall that a homogeneous mixture is a uniform blend of two or more elements or compounds that are not bonded together and, therefore, retain their own identities and properties, and can be separated from one another. Because a solution must be homogeneous, its constituent chemicals must be present throughout the mixture in approximately the same ratio.
Salt water is an example of a homogeneous mixture, as it contains two distinctive chemicals, a "salt," which is most often sodium chloride, NaCl, that is evenly-distributed in water, H2O. When these two compounds are mixed with one another, they do not undergo a chemical reaction, and, therefore, the chemical formulas and properties that are associated with these substances are relatively unchanged. Finally, these compounds can be separated from one another by boiling the water, which could be isolated as condensation, and the salt would remain as a residue.
The following sections of this chapter will present and apply a variety of concepts that are related to the study of solutions.