Which of the following correctly describes why covalent compounds generally have low melting and boiling poin…

Question

Which of the following correctly describes why covalent compounds generally have low melting and boiling points?
(A) The covalent bonds within each molecule are weak.
(B) The inter-molecular forces between covalent molecules are weak, even though intra-molecular bonds are strong.
(C) Covalent compounds do not contain any bonds, only loosely associated atoms.
(D) The electrons in covalent compounds are free to move, reducing the energy needed to separate molecules.

Accepted Answer

## Model Answer **(B)** The inter-molecular forces between covalent molecules are weak, even though intra-molecular bonds are strong. Source: Chapter 4, Section 4.1 (Bonding in Carbon – The Covalent Bond) ## Explanation The textbook explicitly states: *"Covalently bonded molecules are seen to have strong bonds within the molecule, but inter-molecular forces are weak. This gives rise to the low melting and boiling points of these compounds."* So it is the **weak inter-molecular forces** (not weak covalent bonds) that explain low melting/boiling points. Options A, C, and D are factually incorrect as per the passage.

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