OCR A2 Chemistry F324: Arenes


General definitions:

  • Arenes - Are aromatic hydrocarbons containing one or more benzene rings.
  • Electrophile - An electron pair acceptor.
  • Electrophilic substitution of Benzene - A H atom on the benzene ring is replaced by an electrophile. The electrophile is attracted to the electron-rich pi bond where it accepts a pair of electrons from the pi bond to form a new covalent bond with a C atom of the ring.
  • Reflux - The continuous boiling and condensing of a liquid mixture.
  • Phenol's common uses - Antiseptics, disinfectants, plastics and resins in paints.

Reactions (simplified, without conditions or reagents):

- Nitration of Benzene

C6H6 + HNO3 --> C6H5NO2 + H2O

(Where one of the H atoms is replaced by an NO2 group)

- Chlorination (or Bromination) of Benzene

C6H6 + Cl2 --> C6H5Cl + HCl

(Where one of the H atoms is replaced by a Cl atom)

- Phenol (‘acid’) + Alkali

C6H5OH + NaOH(aq) --> C6H5ONa + H2O

(Where O- and Na+ form an ionic bond)

- Phenol (‘acid’) + Sodium

C6H5OH + Na(s) --> C6H5ONa + ½H2

(Where O- and Na+ form an ionic bond)

- Phenol + Br2

C6H5OH + 3Br2 --> C6H2Br3OH + 3HBr

(Where 3 H atoms are replaced by Br atoms (C6H2Br3OH = 2,4,6-tribromophenol))

Evidence against Kekulé’s model of


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