On dilution there is a regular increase in the molar conductivity of strong electrolyte, due to the decrease in solute–solute interaction.
Friedrich Kohlrausch in 1875–1879 established that to a high accuracy in dilute solutions, molar conductivity can be decomposed into contributions of the individual ions.
Instead it can be expressed as a sum of ionic contributions, which can be evaluated from the limiting molar conductivities of strong electrolytes containing the same ions.
For the cation: and for the anion: Most monovalent ions in water have limiting molar ionic conductivities in the range of 40–80 S cm2 mol−1.
Exceptionally high values are found for H+ (349.8 S cm2 mol−1) and OH− (198.6 S cm2 mol−1), which are explained by the Grotthuss proton-hopping mechanism for the movement of these ions.
[4] The H+ also has a larger conductivity than other ions in alcohols, which have a hydroxyl group, but behaves more normally in other solvents, including liquid ammonia and nitrobenzene.
Ostwald's law of dilution, which gives the dissociation constant of a weak electrolyte as a function of concentration, can be written in terms of molar conductivity.