Question

State and explain kohlrausch's law of mobilities

Answer 1

Kohlrausch's law states that the equivalent conductivity of an electrolyte at infinite dilution is equal to the sum of the conductances of the anions and cations. If a salt is dissolved in water, the conductivity of the solution is the sum of the conductances of the anions and cations

Answer 2

Explantion :

Kohlrausch's law of mobilities states that, the limiting molar conductivity of an electrolyte is the sum of the limiting ionic conductivities of the cation and the anion each multiplied with the number of ions present in one formula of the electrolyte.

In terms of equivalent conductivities, kohlrausch's law is defined as, the equivalent conductivity of an electrolyte at infinite dilution is the sum of the two values one depending upon the cation and the other upon anion.

$\Lambda^o_{eq}=\lambda^o_{cation}+\lambda^o_{anion}$

Applications of Kohlrausch's law are :

(1) It is used for the calculation of molar conductivity at infinte dilution for weak electrolytes.

(2) It is used for the calculation of the degree of dissociation.

(3) It is used for the calculation of dissociation constant of a weak electrolyte.