Benzene and Alkyl Benzene - Result Question 48

####52. Answer the following with suitable equation wherever necessary

(i) How can you prepare benzene from lime?

(ii) How will you convert toluene to $m$-nitrobenzoic acid?

$(1987,2 M)$

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Solution:

  1. (i) Lime is heated with coke at high temperature and then, hydrolysed to form acetylene. This acetylene on passing red hot tube polymerises to form benzene :

$$ \underset{\text { Lime }}{CaO}+\underset{\text { Coke }}{3 C} \xrightarrow{2000^{\circ} C} CaC _2+CO \uparrow $$

$$ \begin{gathered} CaC _2+2 H _2 O \longrightarrow Ca(OH) _2+\underset{\text { Acetylene }}{C _2 H _2} \ 3 C _2 H _2 \xrightarrow[\Delta]{Cu} \underset{\text { Benzene }}{C _6 H _6} \end{gathered} $$

(ii) $-CH _3$ in toluene is ortho/para directing group, first oxidised to $-COOH$ in order to make it meta directing and then nitrated.



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