All acids release positively charged hydrogen atoms in water. This distinguishes them from bases, which release negatively charged hydroxide ions in water. Most, but not all, acids have a number of similar properties, including taking the form of a fluid, having a sour taste and feeling sticky to the touch. Additionally, most acids produce hydrogen gas when they react with a metal.
A solution’s pH is a measure of its base or acidity. Acids have a low pH because they produce a lot of positively charged hydrogen ions in solution. Bases, by contrast, have high pH values because they produce a lot of negatively charged hydroxide ions that combine with the hydrogen ions to form water. Neutral liquids, such as water, have roughly equal proportions of each type of ion.
While there are exceptions, most acids have a derivative of the word hydrogen at the beginning. Examples of acids include hydrofluoric acid, hydrochloric acid, acetic acid and sulfuric acid. Some acids are very dangerous, such as hydrofluoric acid, while others are edible. Acetic acid, for example, is better known as vinegar. Some acids, such as the hydrochloric acid in stomach acid, are crucial to digestion. L-ascorbic acid is another beneficial acid; most commonly, it is called vitamin C.