Bromothymol blue sodium salt is widely used as a pH indicator in various scientific and industrial applications. It is particularly effective in determining the acidity or alkalinity of solutions within the pH range of 6.0 to 7.6, where it changes color from yellow (acidic) to blue (alkaline). This property makes it valuable in biological and environmental studies, such as monitoring the pH of cell cultures or aquatic systems. In educational settings, it is commonly used in experiments to demonstrate pH changes and titration processes. Additionally, it is employed in medical diagnostics, including respiratory tests, to detect carbon dioxide levels based on pH shifts. Its ease of use and distinct color transition make it a reliable tool for quick and accurate pH assessment.