Question

State Kohlrausch's law of independent migration of ions. Why does the conductivity of a solution decrease with dilution?

Answer 1

According to Kohlrausch's law of independent migration of ions, "at infinite dilution when the dissociation is complete, each ion makes a definite contribution towards molar conductivity of the electrolyte, irrespective of the nature of the other ion with which it is associated."
e.g., For NaCI

${\wedge }_{NaCl}^0={\lambda }_{N{a}^{+}}^0+{\lambda }_{C{l}^{-}}^0$

Conductivity is the conductance of one centimetre cube of the solution. Upon diluting the solution, the concentration of ions per centimetre cube decreases and, therefore, the conductivity decreases.