Does molten lead bromide conduct electricity?

• A. Yes
• B. No
• C. Only when dissolved
• D. Only in solid state

Answer: (A)

Electric conductivity depends on mobile charged particles. In a solid ionic lattice, the ions are fixed in place, so there’s no current. When lead bromide is melted, the lattice breaks apart and the Pb2+ and Br− ions become free to move. Under an electric field, these ions drift and carry charge, so molten lead bromide conducts electricity. It doesn’t need to be dissolved in water for conduction—the molten state itself provides mobile ions. The idea that it only conducts when dissolved isn’t right for this substance, and the notion that it conducts only in the solid state is incorrect for the same reason.