Which of the following is a property of nonpolar covalent compounds?

• A. They are generally soluble in water.
• B. They exist primarily as crystalline solids at room temperature.
• C. They conduct electricity in aqueous solution.
• D. They have low melting and boiling points.

Answer: (D)

Verified step by step guidance

1. Understand the nature of nonpolar covalent compounds: these compounds consist of atoms sharing electrons equally, resulting in no significant partial charges within the molecule.
2. Recall that solubility depends on polarity: since water is polar, nonpolar covalent compounds are generally insoluble in water due to the 'like dissolves like' principle.
3. Consider physical state and structure: nonpolar covalent compounds often exist as gases or liquids at room temperature rather than crystalline solids, which are more typical of ionic compounds or metals.
4. Evaluate electrical conductivity: nonpolar covalent compounds do not dissociate into ions in aqueous solution, so they do not conduct electricity when dissolved in water.
5. Recognize that nonpolar covalent compounds have weak intermolecular forces (like London dispersion forces), which leads to low melting and boiling points compared to ionic or polar covalent compounds.