Question

From the given data, heat of hydration (numerical value) of LiCl, NaCl and KCl in the increasing order is :

• A. $LiCl<KCl<NaCl$
• B. $LiCl<NaCl<KCl$
• C. $LiCl=KCl<NaCl$
• D. $KCl<NaCl<LiCl$

Answer 1

The correct option is D $KCl<NaCl<LiCl$

As hydration energy is proportional to 1/cation size and as we move down the group, size increases so heat of hydration decreases.
$\Delta H_{Hydration}=\Delta H_{hydration}\left(cation\right)+\Delta H_{hydration}\left(anion\right)$
And order is
KCl < NaCl < LiCl