Which of the following acids is NOT present in grapes?

Acetic acid

The correct answer is option 1. Acetic acid.

Acetic acid, also known as ethanoic acid, is a weak organic acid with the chemical formula \(CH_3COOH\). It is commonly found in vinegar and is responsible for its sour taste and pungent odor. Acetic acid is not naturally present in grapes. Instead, it is formed during the fermentation process when alcohol (ethanol) produced by yeast is further oxidized by acetic acid bacteria.

Tartaric acid is a dicarboxylic acid with the chemical formula \(C_4H_6O_6\). It is one of the main acids found in grapes and is primarily responsible for the tart taste of grapes and wine. Tartaric acid naturally occurs in grapes and other fruits.

Malic acid is a dicarboxylic acid with the chemical formula \(C_4H_6O_5\). It is another acid naturally found in grapes and is responsible for the sour taste in unripe fruits. Malic acid contributes to the overall acidity of grapes and is an important component in winemaking.

Citric acid is a weak organic acid with the chemical formula \(C_6H_8O_7\). It is found in citrus fruits such as lemons, oranges, and grapefruits, but it is not a major acid in grapes. While trace amounts of citric acid may be present in grapes, it is not a predominant acid compared to tartaric and malic acids.

In summary, acetic acid is not naturally present in grapes; instead, it is formed during the fermentation process. Tartaric acid and malic acid are the primary acids naturally found in grapes, contributing to their taste and acidity, while citric acid, though present in small amounts, is not a major acid in grapes.