Question

Explain Wurtz reaction.

OR 

Explain the action of sodium with alkyl halides.

Answer 1

(1) When an alkyl halide is treated with metallic sodium in dry ether, the corresponding higher alkane is formed. 

This is called Wurtz reaction or Wurtz coupling reaction.

(2) In this reaction the alkyl radicals from two molecules of the reacting alkyl halide combine or couple to form the higher alkane.

(3) Thus, methyl bromide reacts with sodium in ether to form ethane (C₂H₆), while ethyl bromide under the same conditions forms n-butane (C₄H₁₀).

(4) If a mixture of two different alkyl halides is treated with Na in dry ether, then a mixture of alkanes is obtained called self coupling products. 

For example, 

A mixture of CH₃Br and C₂H₅Br gives propane along with C₂H₆ and C₄H₁₀.