Alkali metals should be stored under which conditions to reduce ignition risk?

Alkali metals should be stored under which conditions to reduce ignition risk?

• A. In water
• B. In air
• C. Under mineral oil
• D. In sealed oil-free containers

Answer: (C)

Alkali metals ignite easily when they touch moisture or air, so the safety goal is to completely isolate them from both. Mineral oil provides a nonreactive barrier that covers the metal and keeps water vapor and oxygen away, preventing the reactions that can lead to ignition. Storing in water would cause a vigorous, exothermic reaction producing hydrogen gas that can catch fire. Storing in air leaves the metal exposed to oxidation and moisture, increasing ignition risk. Sealed oil-free containers still allow contact with air and moisture, so they don’t effectively prevent those reactions. Therefore, sealing them under mineral oil is the safest, most reliable method to reduce ignition risk.

Alkali metals ignite easily when they touch moisture or air, so the safety goal is to completely isolate them from both. Mineral oil provides a nonreactive barrier that covers the metal and keeps water vapor and oxygen away, preventing the reactions that can lead to ignition. Storing in water would cause a vigorous, exothermic reaction producing hydrogen gas that can catch fire. Storing in air leaves the metal exposed to oxidation and moisture, increasing ignition risk. Sealed oil-free containers still allow contact with air and moisture, so they don’t effectively prevent those reactions. Therefore, sealing them under mineral oil is the safest, most reliable method to reduce ignition risk.