What are acids and their properties?

Acids are substances that release hydrogen ions (H⁺) in aqueous solutions. They have a sour taste, turn blue litmus red, and have a pH less than 7. Common examples include hydrochloric acid (HCl), sulfuric acid (H₂SO₄), and citric acid. Acids are corrosive, conduct electricity in solution, and react with metals to produce hydrogen gas. They also react with bases to form salts and water. Acids are classified as strong or weak depending on their ionization in water. They are used in industries and laboratories.