The lattice enthalpy of Lithium fluoride (LiF) is incredibly high due to the small size of cation and anion
The hydration energy of LiF is lower than the lattice energy.
So, LiF is nearly insoluble in water.
LiF has high lattice enthalpy in comparison to LiCl.
But, Lithium chloride (LiCl) has elevated hydration energy than its lattice energy.
So, LiCl is soluble in water.
LiCl is soluble in acetone, due to larger anion in comparison to cation , resulting in polarization.
Therefore, LiCl acquires a covalent character resulting in its solubility in a non-polar solvent like Acetone.
Final Answer:
Hence, LiCl has higher hydration energy and covalent character resulting in its solubility in polar and nonpolar solvents.
LiF has lower hydration energy, so it is insoluble in water.