Covalent compounds have low melting points because:

The solid $NaCl$ is a bad conductor of electricity since:

Covalent molecules are usually held in a crystal structure by

Which one of the following pairs is an example of polar molecular solids?

Solid $CO_2$ is an example of which type of crystal?

The lattice enthalpy of an ionic compound is the enthalpy change when one mole of an ionic compound in its solid state dissociates into its ions in the gaseous state. It is impossible to determine it directly by experiment. Suggest and explain an indirect method to measure the lattice enthalpy of $NaCl_{(s)}$.