The pH 12.00 buffer solution at 25C is used for calibrating and verifying pH meters and electrodes particularly when measuring highly alkaline solutions.

Its purpose is to provide a stable and accurately known pH value of 12.00 at 25C allowing the accuracy and performance of pH-measuring instruments to be checked and adjusted.

A pH 12.00 buffer solution is a standardized alkaline reference solution that resists changes in pH when small amounts of acid or base are introduced. Its stated pH value of 12.00 is valid specifically at 25C because the pH of buffer solutions can vary with temperature.