kohlrausch's law? discuss its application in determination of equivalent conductance of weak electrolyte at infinite dilution and degree of dissociation of weak acid

Answer 1

Kohlrausch's law is a generalization of the relationship between the molar conductivities of ions in an electrolyte solution. It states that the molar conductivity of an electrolyte at infinite dilution is the sum of the molar conductivities of its ions in the solution.

The law can be expressed as:

Λm = λ+ + λ-

Where Λm is the molar conductivity of the electrolyte at infinite dilution, λ+ is the molar conductivity of the cation, and λ- is the molar conductivity of the anion.

In the determination of the equivalent conductance of a weak electrolyte at infinite dilution, Kohlrausch's law can be applied by measuring the conductivity of the solution at various dilutions and extrapolating the data to infinite dilution. By calculating the molar conductivity of the weak electrolyte at infinite dilution using Kohlrausch's law, the equivalent conductance of the weak electrolyte can be determined.

For the determination of the degree of dissociation of a weak acid, Kohlrausch's law can be applied by considering the acid as a weak electrolyte that partially dissociates into its constituent ions. By measuring the conductivity of the weak acid solution at various dilutions and extrapolating the data to infinite dilution, the molar conductivity of the weak acid at infinite dilution can be calculated using Kohlrausch's law. The degree of dissociation (α) of the weak acid can then be determined using the equation:

α = Λobserved / Λcalculated

Where Λobserved is the observed molar conductivity of the weak acid solution at a particular dilution, and Λcalculated is the calculated molar conductivity of the weak acid at infinite dilution using Kohlrausch's law.

Overall, Kohlrausch's law is a powerful tool in the study of electrolyte solutions, allowing for the determination of various important parameters such as equivalent conductance and degree of dissociation of weak electrolytes.