Question

How do ionic and molecular compounds compare in terms of melting points?

Answer 1

The ionic compound and molecular compound differ with each in their physical properties like melting point and boiling point due to their different type of intermolecular attraction.

Complete step by step answer:
Ionic compounds are characterized as those compounds where the atoms or ions are held by ionic bonds. In an ionic compound the charge distribution takes place as an ionic bond is formed of transfer of electrons where one ion forms negative charge and other ion forms positive charge. In ionic compounds, the ions are held together by strong electrostatic interaction.
The molecular compounds are characterized as those compounds where the atoms are held by covalent bonds. The covalent bond is formed by the mutual sharing of electrons by the atoms. In molecular compounds, the atoms are held by weak intermolecular forces.
The melting point of the molecular compound is generally low as compared to the ionic compound because the energy required to break the intermolecular force between the molecules is less as compared to the energy required to break the ionic bond in the crystalline ionic compound.
The ionic compound melts at high temperature and the boiling point of the ionic compound is even more than its melting point.
Example: The melting point of sodium chloride is 801 degree Celsius and the boiling point of sodium chloride is 1413 degree Celsius. The melting point of water is 0 degree Celsius and the boiling point of water is 100 degree Celsius.

Note:
The ionic compounds are formed by the reaction of metal and non-metals whereas the molecular compounds are formed by the reaction between the non-metals. The molecular compounds are sometimes referred to as the covalent compounds.