Why does the temperature of solution change marginally upon addition of sodium chloride to water?
Because the dissolution of sodium chloride is ONLY slightly endothermic.
This reaction is very slightly endothermic. The energy required to breakup the ionic lattice is ALMOST balanced by the formation of ion-dipole bonds between the ion and the solvent water molecules. For other salts, for instance sodium hydroxide, or ammonium chloride, dissolution in water is strongly exothermic (