Why is Wurtz reaction not preferred for the preparation of alkanes containing odd number of carbon atoms? Illustrate your answer by taking one example.

Explanation

For the preparation of alkanes containing odd number of carbon atoms by using Wurtz reaction, it is necessary to use two different types of alkyl halides. Since, two alkyl halides can react in three different ways, a mixture of three alkanes is obtained in the reaction and it becomes difficult to separate the required alkane from the mixture. For example, on using `CH_3I` and `C_2H_5l` for the preparation of propane, a mixture of propane, butane and ethane is obtained as shown below:

This is why Wurtz reaction is not preferred for the preparation of alkanes containing odd number of carbon atoms.