Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

6 Cards in this Set

  • Front
  • Back


Molecular Formula = C6H6

Molecules containing benzene rings are called aromatic compounds

Bonding in Benzene

Benzene is a planar hexagon w/ a π cloud of electrons above and below the ring.

The electrons are fused together p-orbitals.

Spreading the electrons stabilises the molecule.

The bonds aren't in fixed positions (resonance theory)

Kekule vs Benzene structure

1) Expected ∆H of hydrogenation in kekule is -360 kJmol-1 (3 x ∆H of cyclohexene).

Actual ∆H of hydrogenation is -208kJmol-1.

"Enthaply of hydrogenation is less exothermic than the theoretical cyclohexatriene."

2) benzene doesn't react with bromine water at room temp. Cyclohexene does

3) X-ray crystallography shows the bond length to be all the same at 0.139nm, between the length of a

C-C and a C=C bond

Electrophilic Substitution

The first stage of the process is slow and is known as the rate determining step (RDS) of the reaction the second stage is fast as the unstable intermediate breaks down.

Nitration of benzene

Benzene is refluxed in a water bath at 60°C with a mixture of concentrated sulphuric acid (catalyst) and concentrated nitric acid

Halogenation of Benzene

Requires a halogen carrier catalyst (FeBr3 or AlCl3)