amphoteric

It is rated as amphoteric to the element that can develop a reaction like base or as acid. The term comes from the Greek word amphoteric, which translates as "The one and the other".

An amphoteric, therefore, can act as a base or as an acid depending on the substance with which it reacts. The lead, the tin, the aluminum and the zincFor example, they have amphoteric hydroxides or oxides.

It should be noted that, according to the so-called Brønsted-Lowry theory (named for its independent proponents, the Danish Johannes Nicolaus Brønsted and English Thomas Martin Lowry), the reaction between an acid and a base leads to the fact that, from the exchange of a proton, the acid forms its conjugate base and the base forms its conjugate acid. In this way, acids give up protons and bases accept them.

In this framework, among the amphoteric elements we can find the amphiprotic molecules, capable of donating or receiving a proton. The protein and the amino acids they are amphoteric of this class.

These amphiprotic molecules have an acid radical and a base. That is why they act in one way or another according to the environment. Amphoteric substances modify the electric charge of their hydrophilic sector taking into account the pH middle: to counteract said pH, are positioned as acids if they are in a basic medium, while if they are in an acid medium they stand as bases.

The Water it is an amphiprotic substance (an amphoteric). It can act as a base by causing the acid to lose a proton or act as an acid by giving the base a proton.