The statement "the limiting molar conductivity of an electrolyte can be represented as the sum of the individual contributions of the anion and cation of the electrolyte" corresponds to the law
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Kohlrausch Law of Independent Migration of Ions
Each ion makes a fixed contribution to the limiting molar conductivity, whatever ion it is paired with. This is the law of independent migration of ions:
\( \displaystyle \Lambda^{\circ}_m = \nu_+\lambda^{\circ}_+ + \nu_-\lambda^{\circ}_- \)
Why the other options are incorrect
Option (1) Nernst Distribution Law — Incorrect. It states that a solute distributes itself between two immiscible solvents in a constant concentration ratio at a given temperature; it has nothing to do with conductivity.
Option (2) Debye’s Law — Incorrect. Debye’s T3 law gives the heat capacity of solids at low temperatures; the related Debye–Hückel–Onsager work explains why \( \Lambda_m \) of strong electrolytes falls as \( \sqrt{c} \), not the additivity of ionic contributions.
Option (4) Law of Electrochemical Equivalence — Incorrect. This is Faraday’s second law of electrolysis: the masses of substances liberated by the same charge are in the ratio of their equivalent masses.
NCERT (2026-27 edition):
Kohlrausch Law of Independent Migration of Ions
