A Brønsted acid is a substance that can donate a proton (H⁺) to another substance in a chemical reaction. This concept is part of the Brønsted-Lowry theory, which defines acids and bases based on their ability to transfer protons. When a Brønsted acid donates a proton, it forms its conjugate base. Common examples of Brønsted acids include hydrochloric acid (HCl) and sulfuric acid (H₂SO₄). In these cases, the acids release protons into a solution, increasing its acidity. Understanding Brønsted acids is essential in various fields, including chemistry, biology, and environmental science.