Under which condition can ionic compounds conduct electricity?

• A. When they are in solid crystalline form.
• B. When they are dissolved in water or melted into a liquid.
• C. Only when they are mixed with covalent compounds.
• D. Only at very low temperatures.

Answer: (B)

Verified step by step guidance

1. Understand that ionic compounds consist of positive and negative ions held together in a solid lattice structure.
2. Recognize that in solid crystalline form, the ions are fixed in place and cannot move freely, so the compound does not conduct electricity.
3. Know that electrical conductivity requires the presence of charged particles that are free to move.
4. Identify that when ionic compounds are dissolved in water (aqueous solution) or melted into a liquid state, the ions become free to move and carry electric current.
5. Conclude that ionic compounds conduct electricity only when dissolved in water or melted, because this allows the ions to move freely and conduct electricity.