Moderate

When benzene is heated in air with V2O5 at 450°C yields_________________?

Correct answer: B. Maleic anhydride

  • A. Phenol
  • B. Maleic anhydride
  • C. Glyoxal
  • D. Benzoic acid

Explanation

Vapour-phase oxidation of benzene with air over V2O5 at about 450°C cleaves the ring and produces maleic anhydride. This is a catalytic oxidation rather than a simple substitution, so phenol and benzoic acid are not the principal products. Phenol is the likely distractor because it is an oxygen-containing benzene derivative, but the specified catalyst and temperature favour maleic anhydride formation.

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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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