amfoter

Amfoter is a term used in chemistry to describe a substance that can act as both an acid and a base. This dual reactivity is a key characteristic of such compounds. In its acidic capacity, an amfoter substance can donate a proton (H+ ion), while in its basic capacity, it can accept a proton. This property allows amfoter substances to react with both strong acids and strong bases.

A common example of an amfoter substance is aluminum hydroxide, Al(OH)3. When reacted with a strong acid like hydrochloric acid (HCl), it behaves as a base, forming aluminum chloride and water: Al(OH)3 + 3HCl -> AlCl3 + 3H2O. Conversely, when reacted with a strong base like sodium hydroxide (NaOH), it acts as an acid, forming sodium tetrahydroxoaluminate and water: Al(OH)3 + NaOH -> Na[Al(OH)4]. This ability to react with both acids and bases makes amfoter compounds particularly versatile in chemical reactions and buffering systems.

Other examples of amfoter substances include zinc oxide, lead(II) oxide, and certain amino acids. The amphoteric nature of these substances is often dependent on the specific conditions of the reaction, such as pH. Understanding the amfoter nature of a substance is crucial for predicting its behavior in various chemical environments and for designing chemical processes.