Titrimetric Estimation and Phenolphthalein Indicator in Distribution of Benzoic Acid into Water and Benzene-Buffer Solutions
In the chapter, we described the distribution and solubility of the solute benzoic acid in water and various pH benzene-buffer solutions, which were both tested using the titration method. The partitioning of these acids into hydrophilic solvent (water) and hydrophobic solvent (benzene) layers was studied using the shake-flask acid-base titration method over a 24-hour period at 25°C (room temperature). A phenolphthalein indicator has been employed in titrimetric assessment of the solubility of benzoic acid (solute) in aqueous solvent and in various pH buffer solutions, such as acidic (4.0), neutral (7.0), and basic (9.0). This experiment uses phenolphthalein indicator to titrate several pH benzene-buffer solutions (4.0, 7.0, and 9.0) against 0.01, 0.05, and 0.1N NaOH solutions, with the end point presenting a pink colour for each reading. The concentration of benzoic acid in the water and benzene layers is calculated using the normality determination equation and the distribution coefficient of that acid from the Nernst distribution law equation.
Shiv Prakash Mishra,
Faculty of Science (Chemistry), Dr. Rammanohar Lohia Avadh University, Ayodhya-224001, (UP), India.
Please see the link here: https://stm.bookpi.org/PCSR-V4/article/view/8186
Keywords: Benzoic acid, pH effect, solubility, partition coefficient, phenolphthalein indicator