Final answer:
The dissolving of sodium chloride (NaCl) in water is a physical change that involves dissociation, hydration, and an increase in entropy of the system.
Step-by-step explanation:
When sodium chloride dissolves in water, a physical change occurs. This process involves the dissociation of sodium chloride (NaCl) into its constituent ions, Na+ and Cl-. The polar nature of water allows it to perform dissociation due to the attraction between the water molecules and the ionic compounds.
Water molecules surround the ions, with the negative oxygen ends facing the positive sodium ions and the positive hydrogen ends facing the negative chloride ions. This process of surrounding the ions is known as hydration, which stabilizes the ions in solution and prevents them from reassociating.
Dissolving NaCl in water not only separates the ions but also results in an increase of the system's entropy. Despite the ordered arrangement around each hydrated ion slightly decreasing entropy, the overall change is positive, indicating a spontaneous process favoring dissolution.
Hence, NaCl dissolves in water through a series of ion-dipole interactions and solvation, leading to a stable aqueous solution of dissociated ions.