Used as a pH indicator in acid-base titrations, typically in the range of pH 4.4 to 6.2. It turns red in acidic solutions (below pH 4.4) and yellow in neutral or slightly basic solutions (above pH 6.2). Commonly applied in microbiology for methyl red tests to detect mixed acid fermentation by bacteria, especially in identifying Enterobacteriaceae. Also used in analytical chemistry for endpoint detection in titrations involving weak bases and strong acids. Suitable for use in educational labs and quality control settings where visual pH determination is needed.