Among $\ce{H+, Li+, K+, Rb+, Cs+}$ in an aqueous medium at infinite dilution at 25 °C, which ions have more ionic molar conductivities than that of $\ce{Na+}$?

I know that Molar conductivity is directly proportional to mobility, which is inversely proportional to hydration energy. By that logic, $\ce{K+, Rb+}$, and $\ce{Cs+}$ have molar conductivities that are greater than $\ce{Na+}$'s, but turns out, $\ce{H+}$'s molar conductivity is also higher in comparison with that of $\ce{Na+}$'s. Why is that so?

  • $\begingroup$ Do you know the ancient fable about a race run between a hare/rabbit and a turtle? Apply it. $\endgroup$
    – Poutnik
    Feb 19, 2022 at 15:43
  • $\begingroup$ @Poutnik Slow and steady wins the race? But here, the faster the ion moves, more is it's conductivity right? $\endgroup$
    – Boson
    Feb 19, 2022 at 16:06
  • $\begingroup$ No, try to fill the gaps. :-) The turtle won, because of cheating. The turtle ( or rather a land tortoise instead of a sea turtle) that started the race was not the same as the one that finished it. $\endgroup$
    – Poutnik
    Feb 19, 2022 at 16:15
  • $\begingroup$ High mobility of hydronium and hydroxide ions is directly related to proton exchange between water molecules and respective ions. See also chem.libretexts.org/Bookshelves/General_Chemistry/… $\endgroup$
    – Poutnik
    Feb 19, 2022 at 18:18
  • 1
    $\begingroup$ A similar question: chemistry.stackexchange.com/questions/64984/… $\endgroup$
    – Buck Thorn
    Feb 19, 2022 at 18:47


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