Acid-base reactions are chemical processes that involve the transfer of protons (H⁺ ions) between substances. An acid is a substance that donates protons, while a base accepts them. When an acid and a base react, they typically produce water and a salt, demonstrating a neutralization reaction. These reactions are important in various fields, including chemistry, biology, and environmental science. They help explain processes like digestion in the human body and the behavior of substances in natural waters. Understanding acid-base reactions is essential for studying chemical equilibria and the pH scale, which measures acidity or alkalinity.