Question

how the amine neutralizes the HCl.

explain why amino acids can neutralize acids (act as bases) and neutralize bases (act as acids). (Proteins, made from amino acids, are also amphoteric. This makes proteins one of the body's important buffer systems)

how the amine makes the solution basic.

what must a base do to neutralize an acid (HCI) . i.e. make the acid no longer dangerous?

Answer 1

1) Aliphatic and aromatic amines contain amino (-NH₂) group. The N atom in the amine has a non-bonding electron pair that can pick up the proton from HCl to form protonated amine salt. It is due to the formation of a salt that an amine can neutralize HCl as shown below.

3) An amine contains amino (-NH₂) group. The N atom in amine has a non-bonding electron pair that can be donated to an electron-deficient species. Consequently, an amine is a Lewis base and therefore, reacts with Lewis acids.

4) Abase must have one or more non-bonding electron pair(s) that can be easily donated to an electron-deficient species. HCl is a Lewis acid and therefore, accepts electron density from a Lewis base to form a salt. Therefore, in order to render HCl harmless, i.e, form a salt, a base must have one or more non-bonding electron pair(s) that can be easily donated.