MCQ Detailed View

Ozone (O₃) is formed in the stratosphere, the upper layer of the atmosphere. Oxygen molecules (O₂) are split into individual oxygen atoms (O) by ultraviolet (UV) rays from the sun. These oxygen atoms then combine with O₂ molecules to form ozone (O₃).

UV rays provide the energy needed to break the strong O=O bond in oxygen molecules. This process protects life on Earth by absorbing harmful UV radiation. Other factors like free radicals, cosmic rays, or nitrogen oxides do not directly form ozone in the upper atmosphere.

Understanding ozone formation is important in environmental chemistry because it explains the natural protection of Earth from UV radiation and the balance of atmospheric gases.