Answer: the unshared pair of electrons on the nitrogen can accept a proton
Step-by-step explanation:
According to the Lewis concept, an acid is defined as a substance that accepts electron pairs and base is defined as a substance which donates electron pairs.
Amines have a general molecular formula of
which has lone pair of electrons on nitrogen and thus is able to donate electrons to a lewis acid which is short of electrons. In other words nitrogen can accept a proton.
