The vibrant world of chemistry often relies on visual cues to understand complex reactions and concentrations. Among the most fascinating are pH indicators, substances that change color in response to variations in acidity or alkalinity. Cresol Red (CAS 1733-12-6), a prominent member of the sulfonphthalein dye family, exemplifies this principle with its distinct color shifts. As a leading manufacturer and supplier of fine chemicals, we appreciate the intricate chemistry that makes our products so valuable.

Cresol Red's ability to act as a pH indicator stems from its molecular structure, which undergoes reversible changes in its electronic configuration as it gains or loses protons (H+) in solution. These structural alterations affect how the molecule absorbs and reflects light, resulting in observable color changes. Specifically, Cresol Red exhibits two distinct pH transition ranges:

Firstly, in a strongly acidic environment, Cresol Red appears red. As the pH increases, it transitions from red to orange and then to yellow around pH 1.8-2.0. This first transition is less commonly relied upon for precise titrations compared to its second range.

The more significant and widely utilized transition occurs in a neutral to slightly alkaline range. Here, Cresol Red shifts from yellow at pH approximately 7.2 to a distinct purplish-red at pH around 8.8. This broader range makes it particularly useful for titrations involving weak acids and strong bases, or weak bases and strong acids where the equivalence point falls within this pH window.

The sensitivity and clarity of these color changes make Cresol Red an indispensable chemical reagent for a variety of analytical applications. From laboratory titrations to broader industrial monitoring, its predictable color transitions provide crucial insights. For procurement professionals seeking high-quality Cresol Red that consistently demonstrates these chemical properties, partnering with a reliable China manufacturer ensures access to a product that meets rigorous analytical standards.