Final answer:
Type D fire extinguishers are specifically designed for combustible metals such as magnesium and zinc. A CO₂ extinguisher is not effective against magnesium fires, as the metal can continue to burn in the presence of CO₂. It is important to use the correct extinguishing medium for metal fires to ensure safety and effectiveness.
Step-by-step explanation:
Type D fire extinguishers are used for combustible metals such as zinc and magnesium. When metals like magnesium burn, they can react with CO₂, producing substances like magnesium oxide and carbon, as represented in the chemical equation 2Mg(s) + CO₂(g) → 2MgO(s) + C(s). This reaction indicates that a CO₂ fire extinguisher will not effectively extinguish a magnesium fire. Furthermore, metals in Group 12, like zinc, also require specialized extinguishing mediums found in Type D extinguishers.
Instead of using water, foam, or general-purpose dry powder extinguishers, which can be dangerous or ineffective on combustible metal fires, it's crucial to use a Class D extinguisher. These are designed specifically to handle the unique properties of burning metals. The bright white light produced by burning magnesium highlights its reactivity, also making it useful in applications like flares and fireworks which require high-intensity light.