Why it LiF almost insoluble in water while LiCl is soluble not only in water but also in acetone ?

Explanation

Both `Li^(+) and F^(-)` have small size and therefore LiF has very high lattice enthalpy . Although hydration enthalpy of LiF is also high but it is less than lattice enthalpy. (Lattice enthalpy of LiF= -1045 kJ, hydration enthalpy of Lif=-1034kJ `" mol"^(-1)). But LiCl has lower lattice enthalpy than corresponding hydration enthalpy and therefore , is soluble in water . LiCl has also some covalent character because of greater polarization and hence it is also readily soluble in non-polar solvents such as acetone.