Hydrogen chloride (HCl) has a melting point of -114.2 °C. Sodium chloride (NaCl) has a melting point of 801 °C. Explain in terms of structure and bonding why these substances have such different melting points?

Hydrogen chloride has a simple molecular structure. The atoms within the molecule are held together by strong covalent bonds. However, for simple covalent molecules to melt only the weak intermolecular forces need to be overcome (not the strong covalent bonds). This requires very little energy and thus the melting point is low.
Sodium chloride is a giant ionic lattice. To melt the substance the strong electrostatic attractions between oppositely charged ions (ionic bonds) must be overcome. This requires large amounts of energy and thus the melting point is high.

AJ
Answered by Alexander J. Chemistry tutor

29186 Views

See similar Chemistry GCSE tutors

Related Chemistry GCSE answers

All answers ▸

What is cracking of hydrocarbon molecules?


Sodium Hydroxide can react with sulfuric acid in an acid base reaction. Outline the equation for this reaction, name the product. Finally a titration reaction is conducted. Determine the mass of NaOH needed to neutralise 12.4cm^3 of 0.10moldm^-3 H2SO4.


Give the pH of an alkaline solution


How to balance a chemical equation.


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2025 by IXL Learning