Aqueous solutions are solutions in which the solvent is water, which 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-loving') do. Reactions in aqueous solutions are usually double-displacement reactions. 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).