Reactive chemicals are substances that can undergo rapid chemical changes when they come into contact with other materials. These changes can result in various reactions, such as explosions, fires, or the release of toxic gases. Common examples include sodium, which reacts violently with water, and hydrogen peroxide, which can decompose and release oxygen gas. Handling reactive chemicals requires caution and proper safety measures. They are often stored in controlled environments to prevent accidental reactions. Understanding their properties and potential hazards is essential for safe use in laboratories, industries, and other settings where they may be present.