A Brønsted base is a substance that can accept protons (H⁺ ions) in a chemical reaction. This concept is part of the Brønsted-Lowry theory, which defines acids as proton donors and bases as proton acceptors. When a Brønsted base accepts a proton, it often forms a conjugate acid, which can then participate in further reactions. Common examples of Brønsted bases include ammonia (NH₃) and sodium hydroxide (NaOH). These substances can increase the pH of a solution by reducing the concentration of hydrogen ions. Understanding Brønsted bases is essential in fields like chemistry and biochemistry, where acid-base reactions play a crucial role.