For NaCl, lattice energy = - 186 kcal/mol, the solvation energy of Na+  and  Cl−  are  −97  and  −85 kcal/mole respectively. Therefore for NaCl (s)

Lattice energy or Breaking energy is + 186 kcal/moleΔHsolv  =−97−85=−182  kcal/mol−LE=+186  kcal/molΔHsolution  =+186−182=4   kcal/mol &  endothermic.