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

27780 Views

See similar Chemistry GCSE tutors

Related Chemistry GCSE answers

All answers ▸

16.4 g of Ca(OH)2 was reacted with HCl in a reaction. What was the expected mass of CaCl2, given the mass of the reactant Ca(OH)2 was 12.6 g? What is the percentage yield of the reaction? ( Give all answers to 3 significant figures)


If an element has an atomic mass of 19 and a proton number of 9, how many neutrons does it have and how many electrons does it have?


Give the reagents and conditions needed to convert a secondary alcohol into a ketone. Name the process which occurs during the conversion.


Why can metals conduct electricity?


We're here to help

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

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences