How is pH defined in a solution?

pH is defined as the measure of the concentration of hydrogen ions in a solution. Specifically, it quantifies the acidity or alkalinity of that solution. The pH scale typically ranges from 0 to 14, with values less than 7 indicating acidic solutions (higher concentrations of hydrogen ions), values equal to 7 representing neutral solutions (where hydrogen ions are in balance with hydroxide ions), and values greater than 7 indicating basic or alkaline solutions (lower concentrations of hydrogen ions).

This concept is fundamental in chemistry and environmental science as it affects various chemical reactions, biological processes, and the solubility of substances in water. Knowing the pH of a solution can help determine its suitability for specific applications, including agricultural practices, water treatment processes, and assessing ecological health. The relationship between pH and hydrogen ions is logarithmic, meaning that each one-unit change in pH represents a tenfold change in hydrogen ion concentration, making it an essential metric in many scientific fields.