Hydrocarbons Ques 78

78. The correct order of reactivity towards the electrophilic substitution of the compounds aniline (I), benzene (II) and nitrobenzene (III) is

[2003]

(a) I $>$ II $>$ III

(b) III $>$ II $>$ I

(c) II $>$ III $>$ I

(d) I $<$ II $>$ III

Show Answer

Answer:

Correct Answer: 78.(a)

Solution:

  1. (a) Amino group is ring activating while nitro group is deactivating. Hence, correct order is aniline $>$ benzene $>$ nitrobenzene.

I $>$ II $>$ IIINc1ccccc1

I

<img src=“https://cdn.mathpix.com/cropped/2024_02_27_6f6f5e8b3b9182b8c88fg-148.jpg?height=134&width=139&top_left_y=2077&top_left_x=1424)

IIO=N+c1ccccc1

III $-NO_2$ is an electron attracting group hence decrease the electron density on ring, whereas $NH_2$ group is electron releasing group hence increase electron density on ring. Benzene is also $e^{-}$rich due to delocalization of electrons.