HNO3, or nitric acid, is a strong acid commonly used in laboratories and industries. It is a colorless liquid that can appear yellow due to the presence of nitrogen dioxide. HNO3 is highly corrosive and can cause severe burns, making it important to handle it with care. It is often used in the production of fertilizers, explosives, and in the manufacturing of dyes. In addition to its industrial applications, HNO3 plays a role in the nitrogen cycle, where it contributes to soil fertility. When mixed with water, it dissociates into hydrogen ions and nitrate ions, which are essential nutrients for plants.