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CBSE Class 12 Chemistry 2019 Delhi Set 1 Solved Paper

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Question : 21 of 27
Marks: +1, -0
(i) Out of (CH3)3C−Br\mathrm{(CH_3)_3C-Br} and (CH3)3C−I\mathrm{(CH_3)_3C-I}, which one is more reactive towards SN1\mathrm{S_N1} and why?
(ii) Write the product formed when p-nitrochlorobenzene is heated with aqueous NaOH\mathrm{NaOH} at 443 K\mathrm{K} followed by acidification.
(iii) Why dextro - and laevo - rotatory isomers of Butan-2-ol are difficult to separate by fractional distillation?
Solution:  
(i) Within a group, larger atoms are better nucleophiles. I−>Br−>Cl−>F−\mathrm{I}^- > \mathrm{Br}^- > \mathrm{Cl}^- > \mathrm{F}^-, therefore I−\mathrm{I}^-is better leaving group than Br−\mathrm{Br}^-.
(ii)
The presence of an electron withdrawing group (−NO2)\mathrm{(-NO_2)} at ortho- and para-positions increases the reactivity of haloarenes.
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