A common measure of the acidity or alkalinity of a solution is called pH. This logarithmic scale ranges from 0 to 14, with values below 7 indicating acidity, 7 being neutral, and above 7 suggesting alkalinity. The pH of a solution affects various chemical reactions, biological processes, and nutrient availability in environments. Monitoring and managing pH levels are crucial in fields like agriculture, environmental science, and healthcare, ensuring that conditions are suitable for optimal growth and development.