An aqueous solution is a solution in which the solvent is water. It is usually shown in chemical equations by appending (aq) to the relevant formula. The word aqueous means pertaining to, related to, similar to, or dissolved in water. As water is an excellent solvent as well as naturally abundant, it's a ubiquitous solvent in chemistry. Substances that don't dissolve well in water are called hydrophobic ('water fearing') whereas those that do are known as hydrophilic ('water-loving'). An exampl… (More on Aqueous)