The molar conductivity of a solution at infinite dilution is known as limiting molar conductivity. In other words, when the concentration of the electrolyte approaches zero, the molar conductivity is known as limiting molar conductivity.
1. The conductivity and molar conductivity of an electrolyte change with the concentration of the electrolyte.
2. As concentration decreases, conductivity decreases for both strong and weak electrolytes.
3. But molar conductivity increases as concentration decreases.
4. The variation is different for strong electrolytes and weak electrolytes.
Λ = K x V
Variation of molar conductivity with concentration
It is shown by Debye-Huckel-Onsager equation as follows
Here, Λ𝑚°= Molar conductivity at infinite dilution
(Limiting molar conductivity)
Λ𝑚= Molar conductivity at V-dilution
A = Constant which depends upon nature of solvent and temperature
C = Concentration
Limiting molar conductivity of Strong electrolytes
Kohlrausch’slaw
The limiting molar conductivity of an electrolyte can be represented as the sum of the individual contributions of the anion and cationof the electrolyte.