Answer:
When you dissolve sodium chloride (NaCl) in water to make brine, the particles of NaCl separate and disperse uniformly throughout the water. This process is known as dissolution or hydration.
In a crystal of solid NaCl, the sodium (Na+) and chloride (Cl-) ions are arranged in a regular, three-dimensional lattice structure held together by strong ionic bonds. However, when NaCl is placed in water, the polar water molecules surround each ion and weaken the ionic bonds, causing the crystal lattice to break apart. The positive ends of the water molecules (hydrogen atoms) are attracted to the negative chloride ions, while the negative ends of the water molecules (oxygen atoms) are attracted to the positive sodium ions.
As the ionic bonds weaken, individual Na+ and Cl- ions are pulled away from the crystal lattice and surrounded by water molecules, forming hydrated ions. The hydrated ions are now free to move around in the water, which allows them to conduct electricity and gives brine its characteristic electrical conductivity.
Overall, the dissolution of NaCl in water results in the separation of the Na+ and Cl- ions, and their dispersion throughout the water. This process is a physical change, as the chemical identity of the Na+ and Cl- ions remains the same before and after dissolving in water