Aliphatic Compounds Containing Nitrogen - Result Question 13
####14. The increasing order of basicity of the following compounds is
।. $NH _2$
III.
I. $\sim^{NH}$
IV.
(2018 Main)
(a) (I) $<$ (II) $<$ (III) $<$ (IV)
(b) (II) $<$ (I) $<$ (III) $<$ (IV)
(c) (II) $<$ (I) $<$ (IV) $<$ (III)
(d) (IV) $<$ (II) $<$ (I) $<$ (III)
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Answer:
Correct Answer: 14. (c)
Solution:
- Key Idea Among the given compounds the basic nature depends upon their tendency to donate electron pair.
Among the given compounds in $N$, Nitrogen is $s p^{2}$-hybridised. This marginally increases the electronegativity of nitrogen which in turn decreases the electron donation tendency of nitrogen. Thus making compound least basic.
Among the rest $-NH _2$ is totally different from others as in this compound lone pair of one nitrogen are in conjugation with $\pi$ bond i.e. As a result of this conjugation the cation formed after protonation becomes resonance stabilised
This equivalent resonance in cation makes $\ddot{H N}^{\ddot{N} _{H _2}}$ most basic among all.
Hence, the correct order is
$$ \text { (II) }<\text { (I) }<\text { (IV) }<\text { (III) i.e. option (c) is correct. } $$
