What is Kohlrauch's law?

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Kohlrausch's law states that the molar conductivity of an electrolyte can be represented as the sum of the individual contributions of its ions.

Kohlrausch's law is also known as the law of independent migration of ions.
It is applicable to strong electrolytes only.
The law states that the molar conductivity of an electrolyte is the sum of the molar conductivities of its cation and anion.
The law is expressed as Λm = Λm⁰ + λ⁺ + λ⁻, where Λm is the molar conductivity of the electrolyte, Λm⁰ is the molar conductivity at infinite dilution, and λ⁺ and λ⁻ are the molar conductivities of the cation and anion, respectively.
The law is useful in determining the degree of dissociation of a strong electrolyte.
For example, the molar conductivity of NaCl at infinite dilution is 126.4 S cm² mol⁻¹. The molar conductivity of Na⁺ and Cl⁻ ions at infinite dilution are 50.1 and 76.3 S cm² mol⁻¹, respectively. Therefore, the molar conductivity of NaCl at infinite dilution can be calculated as 126.4 = 50.1 + 76.3.