Potassium and Sodium are classified as which hazard due to their reactivity with other chemicals?

• A. Reactive
• B. Toxic
• C. Flammable
• D. Radioactive

Answer: (A)

Understanding how chemicals are classified by the way they interact with other substances helps explain this. Potassium and sodium are highly reactive metals, especially with water and air. When they meet water, they react vigorously to form hydroxides and release hydrogen gas, often with enough heat to ignite the gas. This tendency to react violently with common reactants is the defining hazard property for these elements, making “reactive” the best classification. They’re not primarily toxic in the sense of poisoning people, not inherently flammable in a general sense (their danger comes from reactivity rather than flammability alone), and they’re not radioactive. That’s why the reactive category fits best, and why these metals are typically stored under oil or in inert environments to prevent contact with moisture and air.