Choose the correct statement from the following :
The low solubility of \( \mathrm{CsI} \) in water is due to its high lattice enthalpy
\( \mathrm{LiF} \) has least negative enthalpy of formation among alkali metal fluorides
The standard enthalpy of formation for alkali metal bromides becomes less negative on descending the group
Among the alkali metal halides, \( \mathrm{LiF} \) is least soluble in water