Which one of the following salts will have the same value of van't Hoff factor $(i)$ as that of…
Which one of the following salts will have the same value of van't Hoff factor $(i)$ as that of $\mathrm{K}_{4}\left[\mathrm{Fe}(\mathrm{CN})_{6}ight]$.
$\mathrm{Al}_{2}\left(\mathrm{SO}_{4}ight)_{3}$
$\mathrm{NaCl}$
$\mathrm{Al}\left(\mathrm{NO}_{3}ight)_{3}$
$\mathrm{Na}_{2} \mathrm{SO}_{4}$.
Solution
$\mathrm{K}_{4}\left[\mathrm{Fe}(\mathrm{CN})_{6}ight]$ and $\mathrm{Al}_{2}\left(\mathrm{SO}_{4}ight)_{3}$ both dissociates to give 5 ions or $i=5$ $\mathrm{K}_{4}\left[\mathrm{Fe}(\mathrm{CN})_{6}ight] ightleftharpoons 4 \mathrm{~K}^{+}+\left[\mathrm{Fe}(\mathrm{CN})_{6}ight]^{4}$ and $\mathrm{Al}_{2}\left(\mathrm{SO}_{4}ight)_{3} ightleftharpoons 2 \mathrm{Al}^{3+}+3 \mathrm{SO}_{4}^{2-}$