EXPLORANDO A PRÁTICA DOS ÁCIDOS NO ENSINO MÉDIO POR MEIO DA TITULAÇÃO DO VINAGRE

Abstract

Innovation in teaching is a way of encouraging students to develop critical/reflective skills, which cannot be achieved by simply memorizing content. With this in mind, this work proposes the creation of a practical-experimental script to contextualize the theory of acids and bases, which are usually taught in the first grade of high school. Specifically, four brands of vinegar obtained commercially were titrated using sodium hydroxide solution (NaOH). The pH measured using a digital pH meter revealed that sample A was the most acidic, with a pH of 2.45. When the acid-base titrations of the four brands A, B, C and D were carried out, the acid content was 4.08 % (m/V) for sample A, 3.66 % for sample B and 3.84 % for samples C and D. These values indicate that only the vinegar in sample A is within the acidity percentage standardized by the inspection bodies. From the base volume data and the recorded pH of the vinegar, it was possible to construct neutralization titration curves for all brands of vinegar analyzed.However, the practical proposal for titrating vinegar is a robust, easy and effective tool for teaching and learning the concepts of acids and bases in secondary schools.

Keywords: Vinegar titration; High school; Acid-base.