It’s amazing how more than 75% of the earth’s surface consists of water. This includes fresh water, lakes, cold water or basically any water that can be found. But, wait, the question was what we mean by an aqueous solution. Simple! The aqueous solution consists of water. Basically, the aqueous solution is the solution that uses water for breaking or dissolving a substance.
SOLVENT AND SOLUTE
It is, however, important to note down the solvent and the solute. The solvent is any liquid that has the ability to dissolve something. For example, water is the most widely used solvent owing to its composition and abundance. Solutes are the substances that need help for dissolving completely and have the inability to break apart on their own. For example, mud cannot dissolve on its own but when you add a solvent like water to it, it gets dissolved.
But, any substance that is dissolved by some other liquid, and not water, is not called aqueous solution. Instead, it is known to be a non-aqueous solution. Aqueous and water go hand in hand. In a chemical reaction, the aqueous solution is denoted by the symbol “(aq)” followed by the name of the species.
NaCl (s) ⇾ Na+ (aq) + Cl– (aq)
HYDROPHILIC AND HYDROPHOBIC
Even though water is referred to as the universal solvent, water can only be used to dissolve substances which are hydrophilic in nature. Various examples of hydrophilic molecules are bases, salts and even acids. Hydrophobic substances do not get easily dissolved in water and do not help in forming aqueous solution like oils and fats. Dissolution of electrolytes in water helps the ions in the solution to conduct electricity.
According to Arrhenius definition, bases and acids are known to be aqueous solutions. The strong attractive forces that exist between the molecules of water determine the ability of the substance to dissolve in water. It can dissolve in water when the substance is able to match or exceed the existent strength. If it fails to dissolve in water, precipitation takes place.
Aqueous solutions containing strong electrolytes are good conductors of electricity while the ones which contain weak electrolytes do not conduct electricity. Ionization takes place by the strong electrolytes when they get dissolved in water completely. The weak electrolytes only show a smaller degree of ionization in water.
During the calculation of the reaction of aqueous solutions, one has to take care of the molarity and the concentration of the aqueous solutions.