# How is the amino group basic?

According to the Khan Academy, the amino functional group is basic because it can remove $$\ce{H+}$$ from systems. Why is that?

Amino: Charged (forms $$\ce{R-NH3+})$$ at the pH of most biological systems. Since amino groups can remove $$\ce{H+}$$ from solution, they are considered basic.

My current understanding:

• The $$\ce{H+}$$ atoms bond in a polar covalent way with $$\ce{N-}$$. So that means the amino acid does not release that many $$\ce{H+}$$ ions. I can see why this is not acidic.
• $$\ce{N-}$$ also takes electrons from $$\ce{R}$$, which makes $$\ce{R}$$ become $$\ce{R+}$$. This should repel $$\ce{H+}$$ from elsewhere in solutions.

How does this functional group remove $$\ce{H+}$$ from its solutions?

• R-NH2 + H+ -> [R-NH3]+ – Karsten Theis Apr 14 '20 at 3:32
• Right! Totally forgot that N requires 3 more electrons to be stable, not 2. Thanks! But what, then bonds the N to the R? – WeCanLearnAnything Apr 14 '20 at 3:48
• You have that on your own picture. Amin groups are bonded to R. There is equilibrium $\ce{R-NH2 + H2O <=> R-NH3+ + OH-}$ or $\ce{R-NH2 + H3O+ <=> R-NH3+ + H2O}$ It is the same as with ammonia. – Poutnik Apr 14 '20 at 4:28

1. According to Lewis acid-base concept, a molecule with central atom having lone pair can act as proton acceptor. In $$\ce{R-NH2}$$ there are lone pairs over $$\ce{N}$$ atom, which can combine with $$\ce{H+}$$ ions.