Physical and Chemical Properties

Physical Properties of Aryl Halides

1. Aryl halides are colourless liquids or colourless solids with characteristic odour.

2. Boiling point generally increases with increase in the size of aryl group or halogen atom. Boiling point order

Ar – I > Ar – Br > Ar – Cl > Ar – F

3. The melting point of p-isomer is more than o- and m-isomer. This is because of more symmetrical nature of p-isomer.

4. Due to resonance in chlorobenzene, C-CI bond is shorter and hence, its dipole moment is less than that of cyclohexylchloride.

Some Chemical Reactions of Haloarenes

(i) Wurtz -Fittig reaction:

Here Halogen atoms from aryl and alkyl part are taken up by Na atoms and further via free radical mechanism both are joined to each other.

(ii) Fittig reaction:

Exactly same as Wurtz Fittig reactions but No Alkyl Group is taken.