Sodium chloride NaCl has a face-centered cubic FCC crystal structure, also known as the rock salt structure. In this structure, each sodium Na+ ion is surrounded by six chloride Cl- ions, and each chloride ion is surrounded by six sodium ions. This arrangement forms a regular, repeating three-dimensional lattice.The physical properties of NaCl, such as its melting and boiling point, conductivity, and solubility in water, can be attributed to the nature of the ionic bonds and the crystal structure.1. Melting and boiling point: NaCl has a high melting point 801C and boiling point 1413C due to the strong electrostatic forces between the positively charged sodium ions and the negatively charged chloride ions. These ionic bonds require a significant amount of energy to break, which results in the high melting and boiling points.2. Conductivity: In its solid state, NaCl does not conduct electricity because the ions are held in fixed positions within the crystal lattice and cannot move freely. However, when NaCl is dissolved in water or melted, the ions become free to move, allowing the substance to conduct electricity. This is because the electrostatic forces between the ions are weakened, enabling them to move and carry an electric charge.3. Solubility in water: NaCl is highly soluble in water due to the polar nature of water molecules. The positively charged hydrogen atoms in water are attracted to the negatively charged chloride ions, while the negatively charged oxygen atoms are attracted to the positively charged sodium ions. This interaction between water molecules and NaCl ions leads to the dissolution of the ionic lattice and the formation of hydrated ions, which are surrounded by water molecules.In summary, the face-centered cubic crystal structure of sodium chloride and the ionic bonds between Na+ and Cl- ions play a significant role in determining its physical properties, such as high melting and boiling points, conductivity when dissolved or melted, and high solubility in water.