Hydrogen chloride, HCl, is a simple molecular substance. Sodium chloride, NaCl, is an ionic compound. Both compounds contain chlorine. Why does sodium chloride have a much higher melting point than hydrogen chloride?

Q: How do I try a free CIE Chemistry question?

Just tap any of the four options on this page — no signup, no card, nothing to install. You'll see the correct answer and a full mark-scheme-style explanation within a second. Each visit shows a fresh randomly-picked question from the live CIE IGCSE Chemistry bank, so you can keep refreshing to try different ones before deciding whether to create a free account for daily access.

Q: Is Kramizo really free for CIE Chemistry students?

Yes — completely free. Every student gets 45 questions a day on the free plan, across any board and any subject, with no card required and no trial countdown. Kramizo's optional Pro plan removes the daily cap and adds analytics, but the free plan is genuinely free forever. We make money from the small percentage of students who choose to upgrade — not from selling data or ads.

Q: Are the Chemistry questions aligned to the CIE IGCSE syllabus?

Every question is written against the published CIE IGCSE Chemistry syllabus and reviewed for accuracy before being added to the bank. We match the command words (state, describe, explain, evaluate), mark allocations, and difficulty tier you'll see on real CIE past papers. Explanations are written in the style of official examiner mark schemes so students learn exactly what marks are being awarded for.

Question

Hydrogen chloride, HCl, is a simple molecular substance. Sodium chloride, NaCl, is an ionic compound. Both compounds contain chlorine. Why does sodium chloride have a much higher melting point than hydrogen chloride?

Accepted Answer

Strong electrostatic forces between ions in sodium chloride require more energy to overcome than weak intermolecular forces in hydrogen chloride — Award 1 mark for comparing the correct types of forces that must be overcome during melting. A is incorrect because sodium chloride does not exist as molecules; it forms a giant ionic lattice. B is incorrect because it compares the wrong types of bonding—the covalent bonds within HCl molecules are not broken during melting. D is incorrect because sodium chloride is ionic, not metallic.

Answer

The ionic bonds in sodium chloride are stronger than the covalent bonds in hydrogen chloride

Answer

Sodium chloride molecules are larger than hydrogen chloride molecules

Answer

Strong electrostatic forces between ions in sodium chloride require more energy to overcome than weak intermolecular forces in hydrogen chloride

Answer

Sodium chloride contains metallic bonding

One real Chemistry question.No signup. 30 seconds.

One real Chemistry question.
No signup. 30 seconds.