Science (086) — AI-generated practice question

Ethanol is a covalent compound. In covalent compounds, the molecules are held together by weak intermolecular forces, which require little energy to overcome. Hence ethanol has a low melting point (156 K).

Sodium chloride is an ionic compound made up of oppositely charged Na⁺ and Cl⁻ ions held together by strong electrostatic forces of attraction. A large amount of energy is needed to break these forces, resulting in a very high melting point (above 1000 K).

Therefore, the large difference in melting points shows that intermolecular forces in ethanol are much weaker than the ionic forces in sodium chloride.

Source: Chapter 4, Section 4.1 – Bonding in Carbon – The Covalent Bond

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• Examiners want two clear contrasts: weak intermolecular forces (covalent/ethanol) vs. strong electrostatic/ionic forces (NaCl).
• Mention both compounds by name and link the force to the melting point.
• The key phrase from the textbook is: "covalently bonded molecules have strong bonds within the molecule, but inter-molecular forces are weak" — use this logic explicitly.
• Do not just say "covalent is weak, ionic is strong" without explaining why that leads to different melting points.