Asked in HEC Phase II 2017 2017Moderate

Aryl are distinguished by:

Correct answer: D. Orange red colour with CH4/AlCl3

  • A. Baeyer reagent
  • B. Lucas Test
  • C. Decolorization of Br2 in CCl4
  • D. Orange red colour with CH4/AlCl3

Explanation

Option D is correct.When aromatic hydrocarbons are treated with chloroform and aluminum chloride, orange to red colours are obtained. These colours are due to the formation of triarylmethyl cations, Ar3C+ which are formed by a Friedel-Craft reaction followed by a transfer of hydride ion.

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About Benzene and Aromatic Compounds

Benzene has a planar ring of delocalised π electrons, giving aromatic stability and equal carbon-carbon bond lengths. The topic covers resonance, electrophilic substitution reactions such as nitration, halogenation, sulphonation and Friedel-Crafts reactions, along with substituent effects and the distinction between substitution in benzene and addition in ordinary alkenes.

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