Question

CsI is least soluble in water the main reason behind this is:

• A. high Lattice Enthalpy
• B. high Hydration energy
• C. low Lattice Enthalpy
• D. low Hydration energy

Answer 1

Answer: (D)

low Hydration energy

The constituent ions in $CsI$ are $C{s}^{+}$ and $I^{-}$, both of which are larger in size. As a result of this, their hydration enthalpy is very less. Snce solubility in water is directly proportional to hydration enthalpy, $CsI$ is least soluble in water