Phenolphthalein indicator 1% in ethanol

C20H14O4, Indicator Grade, CAS : 77-09-8

Phenolphthalein is a commonly used pH indicator in secondary school laboratories. It is a colorless powder that turns pink in basic solutions and remains colorless in acidic solutions. Students can use phenolphthalein to visually determine the pH of a substance or solution by adding a few drops and observing the color change. The transition from colorless to pink occurs around pH 8.2-10.0. By comparing the resulting color to a pH color chart, students can estimate the pH value. Phenolphthalein is often used in acid-base experiments, titrations, and other chemistry activities, allowing students to understand the concept of pH and the importance of indicators in chemical analysis.

酚酞是中學實驗室常用的pH指示劑。 它是一種無色粉末，在鹼性溶液中變成粉紅色，在酸性溶液中保持無色。 學生可以使用酚酞，透過添加幾滴並觀察顏色變化來直觀地確定物質或溶液的 pH 值。 從無色到粉紅色的轉變發生在 pH 值 8.2-10.0 左右。 透過將所得顏色與 pH 比色表進行比較，學生可以估計 pH 值。 酚酞常用於酸鹼實驗、滴定等化學活動中，讓學生了解pH的概念以及化學分析中指標的重要性。