Question

You are studying solubility and saturation by dissolving table salt (NaCl) in 250 mL of water. You notice that as you increase the temperature of the water (solvent), you have to add more salt to stay at the saturation point for the salt. Explain the chemistry responsible for this observation (i.e., the increasing solubility of the salt as the temperature of the water is raised).

Answer 1

When solute (NaCl in this case) is added to solvent(i.e. water) the kinetic energy of the solvent molecules overcome the attractive forces among the solute particles.NaCl is salt it will dissociate into ions( Na+ and Cl-) . These ions are now surrounded by water molecules . This is the whole process of dissolution.

As we heat the solvent molecules the average kinetic energy of its molecules increases thats why now solvent is able to dissolve more salt molecules so there is increase in solubility.