Electrochemistry 2 Question 22
21. The correct order of equivalent conductance at infinite dilution of $\mathrm{LiCl}, \mathrm{NaCl}$ and $\mathrm{KCl}$ is
(2001, 1M)
(a) $\mathrm{LiCl}>\mathrm{NaCl}>\mathrm{KCl}$
(b) $\mathrm{KCl}>\mathrm{NaCl}>\mathrm{LiCl}$
(c) $\mathrm{NaCl}>\mathrm{KCl}>\mathrm{LiCl}$
(d) $\mathrm{LiCl}>\mathrm{KCl}>\mathrm{NaCl}$
Show Answer
Solution:
- In $\mathrm{LiCl}, \mathrm{NaCl}$ and $\mathrm{KCl}$, anions are same.
Cations have same charge but different size. Smaller cations are more heavily hydrated in aqueous solution giving larger hydrated radius and thus smaller ionic speeds and equivalent conductance.
$\Rightarrow$ Equivalent conductance : $\mathrm{KCl}>\mathrm{NaCl}>\mathrm{LiCl}$
