Open AccessXIII. On the accurate measurement of ionic velocities, with applications to various ions
Publication year - 1906
Publication title -
philosophical transactions of the royal society of london. series a, containing papers of a mathematical or physical character
Language(s) - English
Resource type - Journals
eISSN - 2053-9258
pISSN - 0264-3952
DOI - 10.1098/rsta.1906.0013
Subject(s) - electromotive force , ion , arrhenius equation , ionic bonding , electrolyte , chemistry , conductivity , ionic conductivity , dissociation (chemistry) , salt (chemistry) , thermodynamics , analytical chemistry (journal) , electrode , physics , chromatography , activation energy , quantum mechanics , organic chemistry
According to Arrhenius’ theory of electrolytic dissociation, the conduction of the current in a salt solution is due to the presence of free ions, which, under the influence of an electromotive force, move towards the electrodes with a velocity depending, other conditions being equal, upon the magnitude of the driving force, or fall of potential. This ‘‘ionic velocity” can be determined by means of two quite distinct methods, of which one may be termed the indirect and the other the direct method. The former, or indirect method, was evolved by Kohlrausch on his recognition of the law of the independent migration of the ions, which he thus states : “ The molecular conductivity, μ, of a solution is proportional to the sum of the velocities of the anion and of the cation, μ = constant x (u +v ).” The ratio of these velocities,u /v , had been determined many years previously by Hittorf, whose “ Uberftihrungszahl,” or transport number,p =u /(u +v ), for any salt represents the fraction of the total current that is carried by the anion.