Question

Apply Kohlrausch law of independent migration of ions, write the expression to determine the limiting molar conductivity of calcium chloride.

Answer 1

Kohlrausch law : Kohlrausch’s law states that the equivalent conductivity of an electrolyte at infinite dilution is equal to the sum of the conductances of the anions and cations.

According to him, at infinite dilution , equivalent conductivity of the CaCl₂ is given as , $\Lambda^{\circ}_{CaCl_2}=\Lambda^{\circ}_{Ca^{2+}}+2\Lambda^{\circ}_{Cl^-}$

[ as we know dissociation of CaCl₂ ⇔ Ca²⁺ + 2Cl⁻ ]

Answer 2

Kohlrausch law : Kohlrausch law of independent migration of ions states that in the infinite dilution the dissociation of an electrolyte is complete and thus the ions that constitute the electrolyte contributes definitely. Thus the equivalent conductivity at infinite dlution of an electrolyte is the algebraic sum of the limiting equivalent conductivity of it's constituent ions. The molar equivalent conductivity can also be calculated using the Kohlrausch law.Thus the equivalent conductivity of an electrolyte at infinite dilution is equal to the sum of the conductances of the anions and cations.

According to Kohlrausch law, at infinite dilution the equivalent conductivity of the CaCl₂ is given as ,

[ as we know dissociation of CaCl₂ ⇔ Ca²⁺ + 2Cl⁻ ]

∧CaCl₂ =∧Ca²⁺ +2∧Cl⁻