Why does HCl have a lower melting point than NaCl?

HCl has a simple molecular structure. There are weak intermolecular forces between the molecules. These intermolecular forces need to be broken to melt HCl, this requires a small amount of energy and therefore HCl has a relatively low melting point.NaCl is an ionic compound where oppositely charged ions are held together in ionic bonds by strong electrostatic forces of attraction. It is these bonds that need to be broken to melt NaCl. These are very strong bonds which require a lot of energy to break therefore the melting point is relatively high.