A solid is hard brittle and electrically nonconducting. it's melt (the liquid form of the substance) and an aqueous solution containing the substance conduct electricity. classify solid.

Answer: ionic solid

Explanation:

In an ionic solid, the ions are bound together by strong electrostatic attraction hence they are immobile and the solid is unable to conduct electricity. If this solid is dissolved in water, the ions move apart due to solvation and become mobile hence the solution conduts electricity. Similarly, when the solid melts, the ions also become free and the melt conduct electricity.