Question

Lif is insoluable in water but licl is soluable is water as well as base why

Answer 1

Because in Lif, the lattice enthalpy is very high due to small size of fluoride ion. In this case the hydration enthalpy is very less. Hence, Lif is insoluble in water. whereas In lithium chloride(LiCl),  the lattice enthalpy is very small due to large size of chloride ions & hence its hydration enthalpy is high.Moreover LiCl has partial covalent & partial ionic character due to the polarization of Cl-ions by Li ion.Due to its low hydration energy & partial covalent& partial ionic character LiCl is soluble in water as well as in base.

Answer 2

Lif has high lattice enthalpy compared to licl whereas F is highly EN in comparison to Co.