Question

Describe how water molecules interact with sodium chloride molecules in order for water to dissolve salt.

Answer 1

Answer:

Sodium chloride is an ionic salt that completely dissociates in water.

Explanation:

Sodium chloride in water dissociates according to the equation.

NaCl (aq) → Na + (aq) + Cl- (aq)

While water stays in balance according to the equation

2H2O (l) ⇄ H3O+(aq)  +  OH-(aq).

By dissociating the solute in the solvent, the water molecules pick up the sodium cations as well as the chloride anions to break the bonds in the salt crystals and thus produce the dissolution

If the ions are analyzed separately, we see that Na + interacts with water, so it would be producing sodium hydroxide, releasing protons.  

If the reaction goes in the sense of products, the Na + would increase the concentration of [H +], however being a neutral salt the pH does not vary from 7, so the reaction would never go in the sense of products, but only reagents. That's why as the sodium hydroxide is a strong base, it only promotes the formation of water and the cation.

Na+  +  H2O  ←  NaOH  +  H+

The same situation occurs with chloride, since no matter how much you want to form hydrochloric acid, it dissociates by promoting the formation of water plus the corresponding anion. Na + and Cl- act as too weak conjugate acid and base, so the reaction would never go in the direction of products

Cl-  +  H2O  ←  HCl  +  OH-