Question

why is LiF almost insoluble in water whereas LiCl is soluble in water but also in acetone...???

Answer 1

LiF is insoluble in water whereas LiCl is soluble not only in water but also in acetone .

Reason:

In Lithium fluoride the lattice enthalpy is very high due to small size of fluoride ions. In this case the hydration enthalpy is very less. Hence, LiF is insoluble in water. Where as in lithium chloride the lattice enthalpy is very small due to large size of chloride ions and hence its hydration enthalpy is high. More over LiCl has partial covalent and partial ionic character due to the polarization of Chloride ion by Lithium ion. Due to its low hydration energy and partial covalent and partial ionic character LiCl is soluble in water as well as acetone.