Which of the following substances is an example of a covalent network solid?

• A. Ice (H2O)
• B. Diamond (C)
• C. Carbon dioxide (CO2)
• D. Sodium chloride (NaCl)

Answer: (B)

Verified step by step guidance

1. Understand what a covalent network solid is: it is a type of solid where atoms are bonded by a continuous network of covalent bonds throughout the entire structure, resulting in very high melting points and hardness.
2. Analyze each substance given: Ice (H\_2O) is a molecular solid held together by hydrogen bonds, not a covalent network.
3. Carbon dioxide (CO\_2) is a molecular solid composed of discrete molecules held together by weak intermolecular forces, not a covalent network.
4. Sodium chloride (NaCl) is an ionic solid composed of positive and negative ions held together by ionic bonds, not covalent bonds.
5. Diamond (C) is composed entirely of carbon atoms each covalently bonded to four other carbon atoms in a three-dimensional network, making it a classic example of a covalent network solid.