<P> 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 Arrhenius definitions . </P> <P> 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 precipitate . </P> <P> 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 . </P> <P> 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 . </P>

What ion is produced by an acid in aqueous solution