6.1.2 Electrophilic substitution reactions

    Cards (60)

    • Electrophilic substitution reactions involve the replacement of a hydrogen atom on an aromatic ring by an electrophile
    • Steps in the general mechanism for electrophilic substitution on benzene rings
      1️⃣ Formation of the electrophile
      2️⃣ Electrophilic attack on the benzene ring
      3️⃣ Loss of a proton
    • The electrophilic attack forms a positively charged intermediate.
      True
    • The electrophile substitutes a hydrogen atom on the benzene ring.
      True
    • Benzene's negative charge attracts electrophiles.

      True
    • The second step in electrophilic substitution is electrophilic attack on the benzene ring.
    • In the first step of electrophilic substitution, an electron-seeking species called an electrophile is formed.
    • During electrophilic attack, the electrophile forms a positively charged intermediate by attacking the benzene ring.

      True
    • What happens to Br₂ when it reacts with FeBr₃ in electrophilic substitution reactions?
      Forms Br⁺
    • Electrophilic substitution reactions maintain the aromatic structure of the ring.

      True
    • In the formation of the electrophile, Br₂ reacts with FeBr₃ to form Br⁺
    • Electrophilic substitution reactions are a type of organic reaction.
    • Benzene's pi electrons form a delocalized electron cloud above and below the ring.
    • Benzene's delocalized pi electrons create high electron density in the ring.
    • Regeneration of the aromatic ring involves the loss of a proton.

      True
    • Give an example of how an electrophile is formed in electrophilic substitution reactions.
      Br₂ reacts with FeBr₃ to form Br⁺
    • In the third step of electrophilic substitution, a proton is lost to regenerate the aromatic ring.
    • Order the steps in the general mechanism for electrophilic substitution on benzene rings.
      1️⃣ Formation of the electrophile
      2️⃣ Electrophilic attack on the benzene ring
      3️⃣ Loss of a proton
    • What is unique about the pi electrons in benzene?
      They form a delocalized cloud
    • Benzene is highly attractive to electrophiles due to its partial negative charge from the pi electron cloud.

      True
    • What is the sigma complex in electrophilic substitution reactions?
      A positively charged intermediate
    • The sigma complex is crucial because it allows the aromatic structure of benzene to be maintained during the substitution reaction.

      True
    • In the regeneration of the benzene ring, a proton is lost from the sigma complex.
    • Name four examples of electrophiles used in aromatic substitution reactions.
      Nitronium ions, Sulfonium ions, Halogens, Acyl ions
    • Electrophilic substitution reactions maintain the aromatic structure while introducing the electrophile.
    • Electrophilic substitution reactions are a type of organic reaction.

      True
    • An electrophile is an electron-seeking species.
    • Steps in the general mechanism for electrophilic substitution on benzene rings:
      1️⃣ Formation of the electrophile
      2️⃣ Electrophilic attack on the benzene ring
      3️⃣ Loss of a proton
    • What happens during the electrophilic attack step in the mechanism?
      Br⁺ attacks benzene
    • Benzene features a planar aromatic ring with six carbon atoms and delocalized pi electrons.
    • Benzene's negative charge attracts electrophiles, leading to electrophilic substitution reactions.
      True
    • What type of ring does benzene feature in its structure?
      Aromatic ring
    • The pi electrons in benzene are confined to individual bonds.
      False
    • Benzene is highly attractive to electrophiles due to its negative charge.
    • What type of intermediate is formed in the formation of a sigma complex?
      Positively charged
    • The loss of a proton from the sigma complex regenerates the aromatic structure of benzene.
      True
    • Which electrophile is used in nitration reactions?
      Nitronium ion
    • Nitration of benzene produces nitrobenzene.
    • Aromatic substitution reactions increase the diversity of aromatic compounds in organic synthesis.

      True
    • The electrophile in electrophilic substitution reactions attacks the electron-rich benzene ring.

      True
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