Benzene and Alkyl Benzene - Result Question 8
####12. Match the four starting materials given in Column I with the corresponding reaction schemes provided in Column II and select the correct answer using the code given below the lists.
A.
Codes A B C C D A B C D
(a) $p s q r$
(b) $r \quad p \quad s \quad q$
(c) $r s q p$
(d) $s \quad p \quad r \quad q$
(2014 Adv.)
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Solution:
- PLAN This problem can be solved by using the various concepts synthesis of benzene, electrophilic substitution reaction and directive influence of various substituents, including oxidation and reduction.
$\Rightarrow-OH$ and $-NH _2$ are $o / p$-directing groups.
$\Rightarrow N$-acetylation is more favourable than $C$-acylation.
$\Rightarrow N$-sulphonation is more favourable than $C$-sulphonation.
$\Rightarrow NO _2$ is a meta-directing group.
$\Rightarrow H _2 S \cdot NH _3$ reduces only one $NO _2$ group selectively in the presence of two $NO _2$ groups.
Using above concepts the correct sequence of reaction can be written as
A.
$\xrightarrow[H _2 SO _4]{NaNO _2}$ $O _2$ Here, $N$-sulphonation is more favourable in comparisons to
B.
C.
D.
Above reaction proceeds through oxidation, chlorination and amide formation sequentially.
$\therefore A \rightarrow r, B \rightarrow s, C \rightarrow q, D \rightarrow p$ Hence, the correct choice is (c).
