Answer:
Iron and vermiculite.
Explanation:
Iron and vermiculite are the solid substances used to make a hand warmer. Hand warmers contains iron, water, activated carbon, vermiculite, cellulose, and salt. The high melting, boiling points, hard and brittle are the characteristics of an ionic solid used in hand warmer. Iron is the ionic solid which is used in the hand warmer. Once iron exposed to air, the iron oxidizes and releases heat in the process.
