(a) Wurtz.s reaction : Alkylhalides react with sodium in dry ether to give alkanes. Alkane having double the number of carbons than in alkylhalide is formed.
`2RX + 2Na underset("ether")overset("dry")(rarr) R - R + 2` NaX
(b) Polymerization of ethylene : Polyethylene is formed
`underset("Ethylene")(n(CH_(2) = CH_(2))) rarr underset("Polythene")((C_(2) H_(4))_(n))`
(c) Addition of water to acetylene : When acetylene gas is passed through dil, `H_(2)SO_(4)` in presence of `HgSO_(5)` below `60^(@)C`, it undergoes addition with water forming acetaldehyde.
`underset("Acetylene Water")(HC -= CH + H.OH) underset(30% H_(2)SO_(4))overset(1% HgSO_(4))(rarr) underset("Vinyl alcohol")([CH_(2) = CHOH]) rarr underset("Acetaldehyde")(CH_(3)CHO)`
(d) Nitration of benzene : When benzene is heated with a mixture of conc. `HNO_(3)` and conc. `H_(2)SO_(4)` below `60^(@)C`, one H-atom of benzene is substituted by `NO_(2)` groups and forms nitrobenzene.
