Methyl purple pH indicator is a high-grade reagent supplied by Research Lab Fine Chem Industries. Other chemical names for this compound include, 2-[4-(dimethylamino)phenyl]azobenzoate and Tetrasodium. It is a quinone-imide redox dye used to measure pH in the range of 4.8-5.4. Methyl purple available in the form of a green coloured powder. It is soluble in water and in isopropanol. This reagent is stable when stored under recommended conditions. There are chances that methyl purple may produce hazardous decomposition products like carbon dioxide, carbon monoxide, nitrogen oxides and sulphur oxides when brought in contact with certain compounds or flammable materials. It is incompatible with strong oxidising agents. It may cause skin or eye irritation and is harmful if swallowed. CAS No. 1340- 02-9 Quantity provided: 5 gm/bottle Molecular formula: C67H62N8Na4O14S3 Molecular weight: 1391.414 g/mol 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 purple imparts a purple colour to the solution if the pH is 4.8. If the pH of the solution is 5.4, the solution appears green in colour upon addition of methyl purple.