(N/A) Wurtz reaction: Alkyl halides,when treated with sodium metal in a dry ethereal (moisture-free) solution,yield higher alkanes. This reaction is known as the Wurtz reaction and is primarily used for the preparation of higher alkanes containing an even number of carbon atoms.
Examples:
$i$. Formation of ethane from bromomethane $(CH_3Br)$:
$2CH_3Br + 2Na \xrightarrow{\text{dry ether}} CH_3-CH_3 + 2NaBr$
$ii$. Preparation of butane from bromoethane $(C_2H_5Br)$:
$2C_2H_5Br + 2Na \xrightarrow{\text{dry ether}} C_4H_{10} (n-\text{butane}) + 2NaBr$
Limitations of the Wurtz reaction:
$i$. It is generally limited to the synthesis of symmetric alkanes.
$ii$. If a mixture of two different alkyl halides is used,a mixture of alkanes is formed,which is difficult to separate.
$iii$. It is not suitable for the preparation of alkanes with an odd number of carbon atoms in high yield due to the formation of side products.