Describe any two methods of preaparation of benzene with corresponding equtions. Benzene does not behave like an alkene, why? How do we mthyl benzene from benzens?

Explanation

Preparation of Benzene :
1. When sodium benzoate distilled with sodalime. Benzene is formed .
`underset( "Sodium benzoate") ( C _(6) H _(5) COONa) + NaOH underset( Delta ) overset( Ca O ) to underset( " Benzene") ( C _(6) H _(6) ) + Na _(2) CO _(3)`
2. Polymerisation of Acethylene : When Acetylene gas is passed through red hot Cu or Fe tubes, it polymerises and give Benzene.
`3 C _(2) overset( " red rot Cu") underset( 600^(@)C) to C _(5) H _(6)`
Constitution of Benzene : Benzene molecule coannot be represented by a single structure. It has the following Resonance structures.

The resonance energy of Benzene is 150.48 KJ/mole. Thus, it has more stability. Hence does not undergo additon reactions like alkenes. Benzene is aromatic molecule.
Benzene to toluene (Friedal Craft.s Alkylation) :
Benzene reacts with methyl chloride in presence of `Al Cl _(3)` and formes methyl benzene (Toulene).