The main constituent of vinegar is

The main constituent of vinegar is acetic acid, also known as ethanoic acid [1][t1]. Vinegar is produced through a two-step fermentation process where sugars are converted into ethanol, which is then oxidized by acetic acid bacteria into acetic acid [t5][t9]. Typically, vinegar consists of approximately 5–20% acetic acid by volume, along with water and trace flavorings [t7]. This acid is responsible for the characteristic sour taste and pungent odor of vinegar [t5]. In contrast, other options represent acids found in different natural sources: citric acid is the primary acid in citrus fruits like lemons and oranges [c1][t4], ascorbic acid is commonly known as Vitamin C [t2][t6], and tartaric acid is naturally found in tamarind and grapes [c1][t5]. Acetic acid's concentration, often measured as 'grain strength,' determines the vinegar's potency and its effectiveness as a preservative and flavoring agent [t5].

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 2: Acids, Bases and Salts > Table 2.3 Some naturally occurring acids > p. 28