Final answer:
The Hazard Division of magnesium incendiaries, like flares, is determined by the NFPA 704 Hazard Identification System, indicating a potential high fire hazard. Magnesium burns with a bright light but cannot be extinguished by CO₂ fire extinguishers, which contributes to its high flammability rating under Group 12 in the NFPA system.
Step-by-step explanation:
The Hazard Division (HD) of magnesium in incendiaries, commonly used for flares, can be assessed using the National Fire Protection Agency (NFPA) 704 Hazard Identification System. This system uses a diamond-shaped symbol with four colored sections, each representing different types of hazards - flammability, reactivity, health, and other special considerations. Magnesium is known for its intense and brilliant white light when burning and is used in flares and fireworks due to this property. However, it poses unique risks, such as the inability to extinguish the magnesium fire with CO₂ extinguishers. This is reflected in its NFPA ratings, given under 'Group 12', representing a potential high fire hazard.
As magnesium reacts with CO₂ producing magnesium oxide and carbon as shown in the chemical equation:
2Mg(s) + CO₂(g) → 2MgO(s) + C(s),
magnesium flares would have a high rating in the red (top) diamond for its flammable properties. Magnesium incendiaries require specific caution as indicated by the information provided by the NFPA hazard diamond for chemicals.