JEE Main · 2025 · 29 Jan 2025 · Shift 1 · Redox Reactions and Electrochemistry

For a weak electrolyte, molar conductivity ${\Lambda }_m$ tracks the degree of dissociation $\alpha$ through ${\Lambda }_m=\alpha {\Lambda }_m^{\circ }$. As concentration rises, the dissociation equilibrium is pushed back and $\alpha$ falls off steeply (Ostwald's dilution law gives $\alpha \propto 1/\sqrt{c}$ in the weak-dissociation limit). Plotted against $\sqrt{c}$, this produces a curve that drops sharply as concentration increases, quite unlike the gentle, near-linear fall shown by strong electrolytes. Molar conductivity therefore decreases sharply with increasing concentration.