How do ionic and molecular compounds compare in terms of boiling points?
Ionic compounds have higher boiling points.
The attractive forces between ions are much stronger than those between covalent molecules. It takes about 1000 to 17 000 kJ/mol to separate the ions in ionic compounds. It takes only 4 to 50 kJ/mol to separate the molecules in covalent compounds.
The higher attractive forces cause ionic compounds to have higher boiling points. For example, sodium chloride boils at 1413 °C. Acetic acid is a molecular compound with almost the same molecular mass as NaCl. It boils at 118 °C.