Question

Which of the following is most soluble in water?

• A. $CsCIO_{4}$
• B. $NaCIO_{4}$
• C. $KCIO_{4}$
• D. $LiCIO_{4}$

Answer 1

Answer: (D)

$LiCIO_{4}$

Answer 2

Higher is the hydration energy, more will be the solubility in water. If the cations have different charge then the one with higher charge will have higher hydration energy. Among $CsClO_{4}, NClO_{4}$ and $LiClO_{4}$ all of the cations have $+1$ charge, so for comparing hydration energy size factor will be considered Smaller is the size more will be the hydration energy. Thus, among all cations $Li^{+}$ is smallest in size. Hence , $LiClO_{4}$ is most soluble in water