Which of the following is a property of an ionic compound?

• A. They conduct electricity in solid state.
• B. They are usually malleable.
• C. They exist as discrete molecules.
• D. They have high melting points.

Answer: (D)

Verified step by step guidance

1. Understand what an ionic compound is: Ionic compounds are formed by the electrostatic attraction between positively charged cations and negatively charged anions.
2. Recall the physical properties of ionic compounds: They typically have high melting points due to the strong ionic bonds holding the lattice together.
3. Analyze the options given: Ionic compounds do not conduct electricity in the solid state because ions are fixed in place; they conduct electricity when molten or dissolved in water.
4. Consider malleability: Ionic compounds are usually brittle, not malleable, because when layers shift, like charges repel and the structure breaks.
5. Note the structure: Ionic compounds form extended lattice structures rather than discrete molecules.