Question

Why do electrovalent compounds have high melting and boiling point?

Answer 1

• The chemical bond that is formed by the transfer of electrons from one atom to another is termed as an ionic bond. It is formed when one of the atoms can lose electrons to attain inert or noble gas electronic configuration and the other atom needs electrons to acquire the noble gas configuration.
• Compounds in which atoms are connected to each other via ionic bonds are termed as ionic or electrovalent compounds. Example, Sodium chloride $\left(\mathrm{NaCl}\right)$.
• Melting point is the temperature at which the solid phase of any substance changes to its liquid phase while boiling point is the temperature at which the liquid phase of any substance changes to its vapor phase.
• In electrovalent compounds, the atom that loses electrons form cations (positively charged species) while the atom that gains electrons forms anions (negatively charged species). These charged species interact with each other via strong electrostatic forces.
• Due to the presence of strong electrostatic forces, a large amount of energy is required to separate them from each other.
• Hence, electrovalent compounds have a high boiling point and melting point.