aromatic

• What type of compound is benzene?

  Aromatic compound
• How many carbon atoms are in benzene?

  Six carbon atoms

  
• What type of electrons are present in benzene?

  Delocalised electrons
• What is the bond length in the benzene ring?

  Intermediate length between double and single bonds
• What makes benzene very stable?

  The delocalised electron ring structure
• What was the initial predicted structure of benzene?

  Similar to cyclohexatriene
• What was the predicted enthalpy change of hydrogenation for benzene?

  -360 kJ mol^-1
• What was the actual enthalpy change of hydrogenation for benzene?

  -208 kJ mol^-1
• What are compounds containing benzene called?

  Arenes or aromatic compounds
• Why do arenes have high melting points?

  Due to the stability of the delocalised ring
• Why do arenes have low boiling points?

  They are non-polar molecules
• What makes arenes often insoluble in water?

  They are non-polar molecules
• What is the delocalised ring in benzene susceptible to?

  Attack from electrophiles
• What happens during electrophilic substitution?

  The electron ring is partially destroyed then restored
• What is the electrophile in the formation of nitrobenzene?

  NO₂⁺ ion
• What is produced when concentrated sulfuric acid reacts with concentrated nitric acid?

  A reactive intermediate
• What is removed from the benzene ring during the substitution reaction?

  A hydrogen ion

  
• What type of substitution occurs when the reaction temperature is 55°C?

  Mono-substitution
• What is required for Friedel-Crafts acylation to occur?

  A reactive intermediate from acyl chloride
• What does the benzene ring act as in Friedel-Crafts acylation?

  A nucleophile
• What is the product of Friedel-Crafts acylation?

  A phenylketone
• What is the benzene group referred to in the product of Friedel-Crafts acylation?

  Phenyl group
• In what industries are phenylketones commonly used?

  Dyes, pharmaceuticals, and explosives
• What are the key features of benzene's structure and properties?

  • Aromatic compound
  • Six carbon atoms
  • Six hydrogen atoms
  • Delocalised electrons
  • Intermediate bond lengths
  • Very stable structure

  
• What are the characteristics of arenes?

  • High melting points due to stability
  • Low boiling points as non-polar
  • Often insoluble in water
• What are the steps in electrophilic substitution reactions involving benzene?

  1. Electrophile attacks the delocalised ring
  2. Ring is partially destroyed
  3. Ring is restored
  4. Products formed (e.g., nitrobenzene)

  
• What is the Friedel-Crafts acylation process?

  • Benzene acts as a nucleophile
  • Acyl chloride reacts with aluminium chloride
  • Produces a reactive intermediate
  • Forms a phenylketone