An alkaline substance that has a pH higher than 7. Bases are defined by chemists as a water solution within any chemical compound that consists of a lower degree of hydrogen ion concentration than clean water. Examples of this occurrence are the chemical elements of ammonia and sodium hydroxide. These compounds or bases are categorized as the opposites of acid chemicals. This is due to the fact that acid increases the concentration of hydrogen ions while bses decreases them. However, when combined, bases and acids will nullify each other.