A Guided Inquiry Determination of Acetic Acid in White Distilled Commercial Vinegar

Vinegar, with its main component, acetic acid (CH3 COOH), is vital in many biological processes. The goal of this guided inquiry experiment was to determine how much acetic acid is in commercially available white distilled vinegar. Mini- and micro-titration experiments were performed to answer this question. Potassium hydroxide (KOH) was standardized using two primary standards, oxalic acid (C2 H2 O4 ) and L-Ascorbic acid (C6 H8 O6 ). In both titrations, phenolphsthalein was used as an indicator. Our titration data showed the amount of CH3 COOH in vinegar was significantly lower (2–3%) than the expected amount (4–6%), suggesting there were other possible factors including experimental errors or decomposition. This experiment reinforced MSU-WP’s mission by preparing students for leadership and service in a multicultural, global, and technological society.