Question

Amines are ______in nature.
(A) Acidic
(B) Basic
(C) Neutral
(D) Amphoteric

Answer 1

Hint: By applying Lewis acid-base concept we can find whether it is acid, base or neutral.
Amines molecules have nitrogen atoms which have a lone pair, so they can easily donate electrons.

Complete step by step solution:

* Amine is an organic compound which is derived from ammonia by replacement of one or more hydrogen atoms by the organic groups
* Amines are generally basic in nature as there is the presence of a lone pair of electrons on nitrogen. The basicity of amines can be compared with respect to ammonia, by comparing the availability of pairs of electrons on nitrogen.
* Let’s know why are they basic in nature:
Some main factors which make amine basic:
The nitrogen atoms which are present in amines have a lone pair of electrons which can be donated. According to a theory of Lewis acid-base concept, amines can easily donate an electron pair, so they act as Lewis bases.
* We can also say, the effect of alkyl groups raises the energy of the lone pair of electrons, Thus, the basicity of an amine can be expected to increase with the number of alkyl groups on the amine.

Therefore, from the above statements we can conclude that the correct answer is (b).

Note: In the gas phase, the order of basicity is tertiary> secondary > primary. This is because of the inductive effect of the alkyl groups, spreading the positive charge in the protonated form.
In water, the order is secondary > primary > tertiary. It differs from the gas-phase order because the unprotonated tertiary amine is incapable of hydrogen bonding.