Which of the following is an example of an acid?

Vinegar is an example of an acid because it contains acetic acid, which is responsible for its sour taste and pungent smell. Acetic acid is a weak acid commonly used in cooking and as a preservative. Acids are characterized by their ability to donate protons (H⁺ ions) in solution and typically have a pH level less than 7.

In contrast, the other options do not represent acids. Soap is a base that neutralizes acids and is used for cleaning. Baking soda, or sodium bicarbonate, is also a base and often acts as a mild alkali. Bleach, which typically contains sodium hypochlorite, is a strong oxidizing agent and can be considered a base in terms of its pH level. Understanding the properties of acids and bases is crucial in various applications, including cooking, cleaning, and chemical reactions.