The full form of pH is "Potential of Hydrogen". It is a measure of the concentration of hydrogen ions in a solution, which indicates the acidity or basicity of the solution. The pH scale ranges from 0 to 14, with a pH of 7 being neutral. Solutions with a pH value less than 7 are acidic, while solutions with a pH value greater than 7 are basic or alkaline. The pH value is calculated as the negative logarithm of the concentration of hydrogen ions. The importance of pH lies in the fact that living organisms can only withstand a limited range of pH changes, and any more pH adjustments can make life difficult.