Which property is typically demonstrated by covalent compounds?

• A. They form crystalline solids with high hardness.
• B. They conduct electricity in aqueous solution.
• C. They are usually soluble in water.
• D. They have low melting and boiling points.

Answer: (D)

Verified step by step guidance

1. Understand the nature of covalent compounds: Covalent compounds are formed by the sharing of electrons between atoms, typically nonmetals.
2. Recall the physical properties of covalent compounds: They generally have low melting and boiling points because the intermolecular forces (like Van der Waals forces or hydrogen bonds) holding the molecules together are weaker than the ionic or metallic bonds.
3. Compare with other types of compounds: Ionic compounds tend to form crystalline solids with high hardness and high melting points, and they conduct electricity when dissolved in water due to the presence of ions.
4. Consider solubility and conductivity: Covalent compounds are often insoluble or only slightly soluble in water and usually do not conduct electricity in aqueous solution because they do not produce ions.
5. Conclude that the typical property demonstrated by covalent compounds is having low melting and boiling points due to their molecular structure and weak intermolecular forces.