Aluminum and Iodine

Alternate titles:

Aluminium and Iodine

Purpose:

To demonstrate the spectacular reaction between two solids, aluminum and iodine.

Materials:

• 100mL beaker
• Mortar and pestle

Reagents:

• Crystalline iodine (I₂)
• Powdered aluminum (Al)

Hazards and PPE:

• Solid iodine is an acute toxin. Handle with care.
• Wear approved safety goggles and gloves.

Protocol:

Preparation

1. Place 30g I₂ crystals in a mortar. Grind to a fine powder.
2. Place 6g powdered Al in a small beaker.

Demonstration

1. Add Al to I₂ crystals in the mortar.
2. Grind the two solids together.
   1. Reaction may begin during this process, producing fire and large volumes of purple smoke.
3. If reaction does not begin during grinding, add a few drops of DI H₂O to the edge of the solid mixture and scrape the wet mixture against the mortar with a stirring rod to initiate the reaction.
4. Step away. Large amounts of heat and iodine gas will be released.

Additional Notes:

• Iodine vapor will stain hands and clothing. It will sublime off in several hours.

Disposal:

• Mortar and pestle should be thoroughly soaked in a fume hood to allow for complete reaction of the chemicals. Once the mixture no longer produces bubbles or smoke, even after vigorous mixing/stirring, the solution can be placed in properly labeled waste container with plenty of water. The container should be checked every so often to make sure gas build-up doesn’t occur.

Reactions:

• 2Al_(s) + 3I_{2 (s)} → 2AlI₃

Citations:

1. This demo adapted from the demo library of the Chemistry department at the University of Illinois at Urbana-Champaign.