Kohlrausch’s law of independent migration

Each ion has its own characteristic mobiUty. The total conductivity of the electrolyte is the sum of the conductivities of the positive and negative ions. This is known as Kohlrausch s Law of Independent Migration of Ions. 

Q.22.1 Determine the equivalent conductivity at infinite dilution of the following solutions using Kohlrausch s law of independent migration. 

When the limiting molar conductivities are to be obtained for a series of ions in a given solvent, the first step is to get the limiting molar conductivity of an ion by one of the above methods. Then, the limiting molar conductivities for other ions can be obtained sequentially by applying Kohlrausch s law of independent ionic migration (Section 5.8). 

If Kohlrausch s law of independent ionic migration is applicable to solutions of appreciable concentration, as well as to infinite dilution, as actually appears to be the case, the equivalent conductance of an electrolyte MA may be represented by an equation similar to the one on page 57, viz.. 

At very low electrolyte concentrations, each ion of the electrolyte contributes independently to the molar conductivity. For an electrolyte of the form (A2+) (X2- ) , Kohlrausch s law of independent ion migration can be written as ... 

The following method for computing Ae will make this conception clear. As an example the value of A for acetic acid as a function of the ion concentration will be obtained. The computation depends upon two assumptions the evidence for which has been considered in this chapter. The assumptions are (a) aqueous solutions of sodium chloride, sodium acetate and hydrochloric acid are completely dissociated, and (6) at low ion concentrations the equivalent conductance, X, of the ion constituents of strong electrolytes are independent of the nature of the associated ions, i.ethey follow Kohlrausch s law of independent ion migration. Thus if completely dissociated acetic acid were capable of existence the value of its equivalent conductance Afl hac would be in accord with the relation 20 21-22... 

It is of interest to see whether Kohlrausch s law of independent ion migration which has been shown (page 340) to hold accurately for aqueous solutions is also valid for methyl alcohol solutions. Since transference data are not available a test similar to that for water solutions is not yet possible. If, however, limiting equivalent conductances are independent of the ions with which they are associated the differences of, for instance, the limiting conductances of the sodium and lithium salts of an acid HX should be independent of the nature of the radical X, since... 

Kohlrausch s law of independent ionic migration states that the molar conductivity at infinite dilution, A°, is given by the sum of the values for its ionic components, A + and. ... 

At the infinite dilution limit (c—>0) the dissociation is complete and the ion mobility only depends on the ion-solvent interactions and file ionic and the molar conductivities reach their infinite dilution values X° and A°, respectively. In fliis limit the Kohlrausch s law of independent ion migration (Kohlrausch, 1898)... 

According to Kohlrausch s law of the independent migration of ions, the total molar conductivity of an electrolyte (made of v+ cations and v anions e.g., v+ = 1 and V = 2 for CaClz in water) can be expressed as the summation of ionic... 

According to Kohlrausch s law of the Independent Migration of Ions the equivalent conductivity at infinite dilution of a cation (/l0+) or an anion (/l0 ) depends only on the nature of the ion and properties of the medium, such as... 

Vectorial Character of Current Kohlrausch s Law of the Independent Migration of Ions... 

This is Kohlrausch s law of the independent migration of ions The equivalent conductivity (at infinite dilution) of an electrolytic solution is the sum of the equivalent conductivities (at infinite dilution) of the ions constituting the electrolyte (Table 4.13). 

It is of interest to note from Table XXXII that the equivalent conductance of the chloride ion is almost the same in all four chloride solutions at equal concentrations, especially in the more dilute solutions. This fact supports the view expressed previously that Kohlrausch s law of the independent migration of ions is applicable to dilute solutions of strong electrolytes at equivalent concentrations, as well as at infinite dilution. 

Kohlrausch established that electrolytic solutions obeyed Ohm s law accurately once the effect of the electrolysis products was eliminated by using high-frequency alternating current. Kjohlrausch also showed from the experimental data that the conductivity of a solution couId "Be mposed of separate contributions from each ion this is known as Kohlrausch s law of the independent migration of ions. 

Kohlrausch s law. Ions have independent migrations, and the conductance of a solution is the sum of the conductances of the anions and cations. 

Kohlrausch s law If a salt is dissolved in water, the conductivity of the (dilute) solution is the sum of two values - one depending on the positive ions and the other on the negative ions. The law, which depends on the independent migration of ions, was deduced experimentally by the German chemist Friedrich Kohlrausch (1840-1910). 

Kohlrausch s law AlawdevisedbyGermanchemistFriedrichKohlrausch (1840-1910) that states that the conductivily of a dilute solution is equal to the sum of the independent values. That is, the conductivily of a solution is equal to sum of the molar conductivily of the cations and the molar conductivity of the anions. The law is based on the independent migration of the ions and was deduced experimentally. 

Using Kohlrausch s additivity law of the independent migration of ions, single ion limiting conductivities of all other ions can be obtained. 

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