Final answer:
The melting of sodium chloride requires a lot of energy due to the strong attractions between the sodium cations and chloride anions in its crystal lattice.
Step-by-step explanation:
The reason it takes a lot of energy to melt sodium chloride is because the process of melting an ionic compound requires the addition of large amounts of energy to break all the ionic bonds in the crystal. The melting of sodium chloride requires a lot of energy due to the strong attractions between the sodium cations and chloride anions in its crystal lattice.
Sodium chloride has a high melting temperature of about 801 °C because of the strong attractions between the sodium cations and chloride anions in its crystal lattice. Breaking these attractions requires a lot of energy.