Hydrochloric acid (HCl) is a strong, colorless, and highly corrosive acid that is widely used in industry and laboratory applications. It is a solution of hydrogen chloride gas in water and is commonly known as muriatic acid. Hydrochloric acid is a highly reactive compound that can dissolve many metals and organic materials, and it is also an important component of the gastric acid in the stomach, where it helps in the digestion of food. Hydrochloric acid has a pungent odor and can cause severe burns and eye damage if handled improperly. It is commonly used in the production of PVC plastics, fertilizers, and various other chemicals, and it is also used in the petroleum industry for the removal of impurities from oil and gas wells.