Question

The correct order of Basicity of the following amines is

(A) $I>II>III>IV$
(B) $I>III>II>IV$
(C) $III>II>I>IV$
(D) $IV>III>II>I$

Answer 1

In this question, we have been provided with amines we need to arrange them in order of their basicity so that we know that basicity depends on the presence of a lone pair or the electron-donating group. More the number of lone pair or electron-donating groups will be the basicity. So, this would help us in the arrangement of amines.

Complete step by step solution:
We have been provided with amines,
So, when we talk about basicity, we know that more the number of lone pair more will be the basicity or we can say that a greater number of Electron donating group more will be the basicity,
So, we can say that basicity increase with the increase in the number of electron-donating groups or lone pair,
Also, if there is an electron-withdrawing group it would have the least basicity.
Now we have been provided different amines,
So, in (I) is amine there would be no resonance of the lone pair of “N” and we know that presence of lone pair indicates higher basicity,
Now, in (III) is amine we have a methyl group attached so +I effect of the methyl group and resonance of lone pair of “N” increase the basicity,
Next, we have (II) is amine in which there is no methyl group attached so basicity will be less than that of (III) is an amine
At last, we have (IV) amine in which here is $N{{O}_ {2}}$ group attached so the effect of -I effect of $N{{O}_ {2}}$ group will decrease the basicity of this amine.
On comparing the above result the order of basicity would be: $I>III>II>IV$.

We can say that option (B) $I>III>II>IV$ is correct.

Note: In this question do not get confused between the electron-donating and the electron-withdrawing group as basicity increases with the electron-donating group and decreases with the electron-withdrawing group, otherwise the arrangement would become incorrect. Most aliphatic amines are not highly toxic, and many are harmless, natural components of foods and pharmaceuticals. Larger amines (12 or more carbon atoms) are usually less irritating. Aromatic amines are also irritants and can be absorbed through the skin. They may be dangerous poisons.