Metanil Yellow 0.1 % indicator solution is a diluted solution of the synthetic azo dye Metanil Yellow and is mainly used in analytics as a pH indicator. This indicator solution is suitable for the determination of pH in aqueous solutions and enables fast and easy detection of acid-base reactions.

The particular suitability of Metanil Yellow 0.1 % Indicator Solution results from its chemical property, which enables it to show color changes depending on the pH of the solution under investigation. In the acidic range, the solution exhibits a yellow coloration, while as the pH increases towards alkaline, it takes on a red coloration. This enables precise differentiation between acidic and alkaline solutions.

The functioning of the Metanil Yellow 0.1% indicator solution is based on a protonation or deprotonation of the dye molecule, which causes a color change. This color change is caused by interactions between the dye and hydrogen or hydroxide ions present in the solution.

Although Metanil Yellow is also used in higher concentrations for staining in histology and medical diagnostics, the primary application of the 0.1% indicator solution is in analytical chemistry for the determination of pH values and the study of acid-base reactions.