The chemical element known for its acidity in solution is Hydrogen, represented by the symbol H on the periodic table. When dissolved in water, hydrogen ions (H⁺) are produced, which contribute to the acidity of a solution. The pH scale is a measure of hydrogen ion concentration, with lower values indicating higher acidity. Acidic substances, such as lemon juice and vinegar, have pH values below 7, while neutral substances, like pure water, have a pH of 7. Understanding acidity is crucial in various fields, including chemistry, biology, and environmental science.