Which of the following is a property of acids?

Acids are known for their distinct sour taste, which is one of their primary characteristics. This sourness is due to the presence of hydrogen ions (H⁺) that acids release in solution, and it is this property that leads to the familiar taste of substances like citric acid in lemons and acetic acid in vinegar. The sour taste is a result of how our taste buds respond to the hydrogen ions produced by the dissociation of acids in aqueous solutions.

The other options—bitterness, slippery feel, and pungent odor—are typically associated with other types of compounds. For example, bases are often linked to a slippery feel because they can react with oils and fats, creating a soapy texture. Bitterness is usually a trait of certain alkaloids and other organic compounds rather than acids. Pungent odors can vary widely among different compounds but are not a definitive property of acids, as many substances across various categories can have strong smells. Thus, the sour taste is a defining characteristic of acids, making it the correct answer.