state and explain kohlrausch law

Kohlrausch law of independent migration of ions:

• This law states that the limiting molar conductivity of an electrolyte can be represented as the sum of the individual contributions of its anion and cation.

Λ^∞_m = v₊ λ^∞₊ + v_- λ^∞_-

Where,  v₊and V_- are the number of cations and anions per formula unit of electrolyte respectively λ^∞₊ and λ^∞_- are the molar conductivities of the cation and anion at infinite dilution respectively.

Example: The molar conductivity of HCl at infinite dilution can be expressed as,

Λ^∞ _HCl = V_H+λ^∞ _H + V_Cl-λ^∞ _Cl-

For HCl, V_H+ = 1  and  V_Cl- = 1.

So, Λ^∞ _HCl = (1 x λ^∞ _H+) + (1 x λ^∞ _H-);

Hence, Λ^∞ _HCl = λ^∞ _H+ + λ^∞ _Cl-

Applications of Kohlrausch 's law: Some typical applications of the Kohlrausch 's law are:

• Determination of Λ∞m for weak electrolytes
• Determination of the degree of ionization of a weak electrolyte
• Determination of the ionization constant of a weak electrolyte 
• Determination of the solubility of a sparingly soluble salt