For a **strong** electrolyte (e.g. KCl), the variation of molar conductivity $\Lambda$ with $\sqrt{c}$ is:

Kohlrausch's experimental observation: $\Lambda = \Lambda_0 - a\sqrt c$ for strong electrolytes. Linear in $\sqrt c$, allowing extrapolation to find $\Lambda_0$. For weak electrolytes the variation is non-linear.