Correct Answer - A
Due to high hydration enthalpy of `Li^(+)` ion, lithium halides are soluble in water except LiF which is sparingly soluble in water except LiF which is sparingly soluble in water due to its high lattice enthalpy. However, as we move down the group, the solubility of alkali metal fluorides increases regularly from LiF to CsF because the decrease in lattice enthalpy more than comensates the decrease in hydration enthalpy.
