Which of the following statements about acids is true?

Acids are characterized by a sour taste, which is evident in many common acidic substances, such as vinegar and citrus fruits. This property is a fundamental characteristic of acids in chemistry. Unlike bases, which are typically bitter, acids will often produce a sour flavor when tasted, making the choice that describes acids as sour the accurate statement.

The other statements do not align with the fundamental properties of acids. For instance, acids generally have a pH less than 7, not greater, and they are also known to produce ions in solution that can react with metals, which makes the option regarding metal dissociation incorrect. Thus, the statement that accurately reflects a true property of acids is that they are sour to taste.