Bromcresolgrønnreagens
Bromcresolgrønnreagens is a chemical indicator used in analytical chemistry. It is a weak acid that changes color depending on the pH of the solution. Specifically, it is a member of the triarylmethane dye family and its chemical structure contributes to its pH-sensitive properties. In acidic solutions, typically below pH 3.8, bromcresol green is yellow. As the pH increases, it undergoes a color transition. In neutral to slightly alkaline solutions, around pH 4.0 to 5.6, the indicator displays a green hue. Above pH 5.6, the color shifts to a distinct blue. This distinct color change makes it useful for titrations, particularly those involving weak acids and strong bases, where the equivalence point falls within its transition range. It is commonly prepared by dissolving bromcresol green in water with the addition of a small amount of sodium hydroxide or sodium carbonate to facilitate dissolution and ensure solubility. Precise concentrations of the indicator solution are important for accurate titration results. Bromcresolgrønnreagens is also sometimes referred to as bromocresol green indicator.