Methyl thymol blue is a high-grade reagent supplied by Research Lab Fine Chem Industries. It is also known as methyl red thymol blue. It is available as a dark green to reddish brown powder. Methyl thymol blue is stable if stored under recommended conditions. It should be stored in an air tight container and kept in a well-ventilated place. When exposed to fire, methyl thymol blue may form hazardous decomposition products like carbon oxides, nitrogen oxides, sodium oxides and sulphur oxides. It is basically a combination of methyl red indicator, which changes from red to yellow at 5.3 pH and thymol blue which turns from red to yellow around pH 2.0, and from yellow to blue (base) around pH 8.8. CAS No. 4310-80-9 Quantity provided: 25 gm/bottle Assay: Minimum Any pH indicator is added in small amounts to a solution to determine the pH of any solution visually. Normally an indicator leads to a change in the colour of the test solution, based on the pH. pH indicators are widely used in titrations to determine the extent of a chemical reaction. Or they may be used in any situations requiring the rough estimate of pH range of any solution. Methyl thymol blue is an indicator that turns red below pH 2.0, orange from pH 2.0 to pH 5.3, yellow from pH 5.3 to pH 8.8, and green above pH 8.8.