Acids are chemical compounds that, when dissolved in water, release hydrogen ions (H+). These hydrogen ions give acids their characteristic sour taste, corrosive properties, and ability to react with certain metals to produce hydrogen gas. Common examples of acids include hydrochloric acid (HCl), sulfuric acid (H2SO4), and nitric acid (HNO3). Acids play a vital role in various chemical processes in everyday life, from industrial applications to human physiology.