Aromatic

• Benzene = C6H6
• Lone electrons in p orbital combine to form delocalised ring of electrons.
• Each carbon is bonded to two other carbon atoms, I hydrogen. The lone electron pair is in p orbital.
• NO2 = Nitro
• OH on benzene = Phenol. OH is priority group.
• NH2 on benzene = phenylamine
• Kekule’s structure is alternating double and single bonds.
• Benzene is more stable than cyclohexene. Measure stability by comparing hydrogenation of both.
• Experimental value for hydrogenation of benzene is -208. Lower than theoretical value which is -360 KJ mol^-1
• Benzene more stable doesn’t allow structure to open up. Due to delocalised electron structure.
• More energy required to break bonds in benzene than cyclohexene.
• Benzene has high electron density because of delocalised ring.
• Friedal-Crafts Acylation = Acylation groups have a very strong positive charge however it is not positive enough. Use halogen carrier to act as a catalyst (AlCl3) produces stronger electrophile more positive charge.
• NO2 is the electrophile and H2SO4 is a catalyst
• How many electrons does carbon have?

  4 electrons
• How is each carbon atom bonded in organic chemistry?

  To 2 other carbons and 1 hydrogen
• What is the final electron in carbon's bonding structure?

  In a p orbital
• What is the significance of delocalized electrons in carbon-carbon bonds?

  They make all C-C bonds the same
• What do lone electrons in the orbital contribute to?

  Delocalized ring of electrons
• What is Kekulé's structure in organic chemistry?

  • Alternating single and double bonds
  • Represents benzene's bonding structure
• How does benzene compare to cyclohexane-1,3,5-triene in stability?

  Benzene is more stable than cyclohexane
• What energy is required to break bonds in organic compounds?

  Energy is required to break bonds
• How does the energy requirement differ between benzene and cyclohexane?

  More energy is needed for benzene
• What does the stability of benzene suggest about its structure?

  Benzene is more stable than cyclohexane
• What is the predicted energy of benzene?

  -360
• What is the actual energy of benzene?

  -208
• What are the reactions involved in Friedel-Crafts acylation?

  • React with acyl chloride
  • Create a strongly positive electrophile
• What is the role of AlCl3 in Friedel-Crafts acylation?

  It acts as a catalyst
• What is the result of the nitration of benzene?

  Concentrated nitric acid is used
• What acids are used in the nitration of benzene?

  Nitric acid and sulfuric acid
• What is the reaction equation for the nitration of benzene?

  $HNO_3 +$$2H_2SO_4 \rightarrow NO_2 +$$H_2O +$$2HSO_4^-$
• What is the stability of double bonds compared to single bonds?

  Double bonds are less stable than single bonds
• How does Kekulé's structure relate to the stability of benzene?

  Kekulé's structure is less stable than benzene
• What is the implication of using Kekulé's structure for benzene?

  It suggests instability in benzene
• What is the effect of using a more stable structure in organic chemistry?

  It leads to more predictable reactions
• How does the energy released during bond formation affect stability?

  More energy released means greater stability
• What is the relationship between energy and reactivity in double bonds?

  Double bonds are more reactive than single bonds
• What does the term "unstable" imply in organic chemistry?

  It indicates a tendency to react
• How does the structure of benzene contribute to its reactivity?

  Benzene's structure makes it less reactive
• What is the significance of the delocalized electrons in benzene?

  They contribute to benzene's stability