Final answer:
A substance is characterized as an acid if it can donate hydrogen ions (H+) when dissolved in water, forming an aqueous solution. Acids have specific nomenclature such as 'hydrochloric acid' for HCl(aq). Organic carboxylic acids also release H+ from the -COOH group.
Step-by-step explanation:
To determine whether a substance is an acid, you can assess its chemical properties and behavior in water. Acids are characterized by their ability to donate hydrogen ions (H+) when dissolved in water, forming an aqueous solution. This definition is in line with the Arrhenius theory of acids and bases. For instance, if hydrochloric acid (HCl) is dissolved in water, it ionizes to produce H+ and Cl- ions, with HCl(aq) indicating that it's in an aqueous solution. Organic acids, such as carboxylic acids (RCOOH), have a different structure but still are considered acids as they can donate a hydrogen ion from their -COOH group. In contrast, substances that start with a metal, a cation, or NH4+ and end with -OH are typically bases, as they produce hydroxide ions (OH-) in water.
Acid nomenclature is important to understand. For example, an acid composed of hydrogen and another element is named with the prefix 'hydro-', followed by the stem of the non-metal element, and ending with the suffix '-ic acid', befitting its status as an acid when dissolved in water. A substance such as HCl becomes hydrochloric acid when in aqueous solution.