A weak electrolyte is an electrolyte that is only partially ionised in solution, so that it exists in equilibrium with its un-ionised form. Because relatively few ions are present, its solutions conduct electricity only weakly. Acetic acid is a weak electrolyte, in contrast to a strong electrolyte, which is fully ionised.

弱电解质是在溶液中只能部分电离的电解质,因而与其未电离的形式处于平衡。由于离子相对较少,其溶液导电能力较弱。乙酸是弱电解质;与之相对,强电解质则完全电离。