The pH scale measures the acidity or alkalinity of a solution, ranging from 0 to 14. A pH of 7 is considered neutral, while values below 7 indicate acidity and values above 7 indicate alkalinity. To calculate pH, you can use the formula: pH = -log[H⁺], where [H⁺] represents the concentration of hydrogen ions in moles per liter. For example, if a solution has a hydrogen ion concentration of 0.01 moles per liter, the pH would be calculated as pH = -log(0.01), resulting in a pH of 2. This indicates a strongly acidic solution. Understanding pH is essential in fields like chemistry, biology, and environmental science.