Kohlrausch Law: This law is in relation to limiting the molar conductivity of an electrolyte to its constituent ions. According to this law, Limiting molar conductivity is equal to the sum of individual molar conductivities of cation and anions that makes up the electrolyte. Kohlrausch law is also known as Kohlrausch Law of Independent Migration. Mathematically, it can be represented as-
λ∞ = λ∞c + λ∞a
λ∞ is the molar conductivity of an infinite solution
λ∞c is the conductivity of a cation in an infinite solution
λ∞a is the conductivity of an anion in an infinite solution
An example of Limiting molar conductivity is Sodium chloride(NaCl). The limiting molar conductivity of sodium chloride is equal to the sum of the limiting conductivity of sodium cation and chloride anion.
[λ∞NaCl = (λ∞Na^+) + (λ∞Cl^-)]
A german physicist Friedrich Kohlrausch during the period from 1875-1879 gave the concept of Kohlrausch law which named after him. His role was important in the development of physical chemistry and was the great influential researcher of electrochemistry during his time. The experiments which he used in order to develop the Kohlrausch law(Kohlrausch Law of Independent Migration) were used by famous and important chemists like Arrhenius, Ostwald and Van’t Hoff(who devised the concept of Ionist theory), they were called the founders of physical chemistry.
Application of Kohlrausch Law
The application of Kohlrausch law are-
- Used for calculation of the dissociation constant of an electrolyte.
- Used for calculation of the limiting molar conductivity of a weak electrolyte.
- This concept of Kohlrausch law is used for degrees of dissociation of weak electrolytes.
- Kohlrausch law is used for solubility constants of various salts.
- Used for calculation of the cell potential in various electrochemical cells. Used for calculation of the cell potential in various electrochemical cells.