Kohlrauschlögmál

Kohlrausch's law, also known as the law of independent migration of ions, is an empirical law in physical chemistry that describes the molar conductivity of an electrolyte solution. It was discovered by Friedrich Kohlrausch in 1876.

The law states that at infinite dilution, the molar conductivity of a strong electrolyte is the sum of the ionic conductivities of its constituent ions. This means that each ion contributes a specific amount to the overall conductivity of the solution, and these contributions are independent of each other.

Mathematically, Kohlrausch's law can be expressed as:

Λ₀ = ν⁺λ⁺ + ν⁻λ⁻

where Λ₀ is the molar conductivity at infinite dilution, ν⁺ and ν⁻ are the stoichiometric coefficients of the cation and anion, respectively, and λ⁺ and λ⁻ are the ionic conductivities of the cation and anion at infinite dilution.

This law is particularly useful for determining the molar conductivity of weak electrolytes, which cannot be directly measured at infinite dilution due to their low degree of dissociation. By measuring the conductivity of strong electrolytes containing the desired ions, their individual ionic conductivities can be determined and then used to calculate the molar conductivity of the weak electrolyte.

Kohlrausch's law also provides evidence for the existence of ions in solution and supports the Arrhenius theory of electrolytic dissociation. It is a fundamental concept in electrochemistry and is applied in various fields, including chemical analysis and the study of ionic solutions.