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
chemical formula. For example, a solution of table salt, or sodium
chloride (NaCl), in water would be represented as Na+(aq) + Cl−(aq).
The word aqueous means pertaining to, related to, similar to, or
dissolved in, water. As water is an excellent solvent and is also
naturally abundant, it is a ubiquitous solvent in chemistry.
Substances that are hydrophobic ('water-fearing') often do not
dissolve well in water, whereas those that are hydrophilic
('water-friendly') do. An example of a hydrophilic substance is sodium
chloride. Acids and bases are aqueous solutions, as part of their
The ability of a substance to dissolve in water is determined by
whether the substance can match or exceed the strong attractive forces
that water molecules generate between themselves. If the substance
lacks the ability to dissolve in water the molecules form a
Reactions in aqueous solutions are usually metathesis reactions.
Metathesis reactions are another term for double-displacement; that
is, when a cation displaces to form an ionic bond with the other
anion. The cation bonded with the latter anion will dissociate and
bond with the other anion.
Aqueous solutions that conduct electric current efficiently contain
strong electrolytes, while ones that conduct poorly are considered to
have weak electrolytes. Those strong electrolytes are substances that
are completely ionized in water, whereas the weak electrolytes exhibit
only a small degree of ionization in water.
Nonelectrolytes are substances that dissolve in water yet maintain
their molecular integrity (do not dissociate into ions). Examples
include sugar, urea, glycerol, and methylsulfonylmethane (MSM).
When writing the equations of aqueous reactions, it is essential to
determine the precipitate. To determine the precipitate, one must
consult a chart of solubility. Soluble compounds are aqueous, while
insoluble compounds are the precipitate. Remember that there may not
always be a precipitate.
When performing calculations regarding the reacting of one or more
aqueous solutions, in general one must know the concentration, or
molarity, of the aqueous solutions.
Look up aqueous solution in Wiktionary, the free dictionary.
Metal ions in aqueous solution Solubility Dissociation (chemistry) Acid-base reaction theories Properties of water
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Zumdahl S. 1997. Chemistry. 4th ed. Boston: Houghton Mifflin Company. p 133-145.
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Ideal solution Aqueous solution Solid solution Buffer solution Flory–Huggins Mixture Suspension Colloid Phase diagram Eutectic point Alloy Saturation Supersaturation Serial dilution Dilution (equation) Apparent molar property Miscibility gap
Concentration and related quantities
Molar concentration Mass concentration Number concentration Volume concentration Normality Percentage solution Molality Mole fraction Mass fraction Isotopic abundance Mixing ratio Ternary plot