n-Butane prepared by Wurtz reaction of ethyl bromide is always contamined by some ethane and ethene . From where do ethane and ethene come in ? Explain.

n-Butane prepared by Wurtz reaction of ethyl bromide is always contami

1.	n-Butane prepared by Wurtz reaction of ethyl bromide is always contamined by some ethane and ethene . From where do ethane and ethene come in ? Explain.
Answer» Solution :Wurtz reaction is believed to occur by free radical mechanism `UNDERSET"Ethyl BROMIDE"(CH_3CH_2Br)+Na to underset"Ethyl radical " (CH_3 oversetdot(CH_2))+NaBr` Ethyl radical thus produced undergoes coupling and disproportionation reaction. Whereascoupling produces n-butane, disproportionation produces ETHANE and ETHENE as SHOWN below : `underset"Ethyl radical"(CH_3oversetCH_2)+CH_2oversetCH_3 overset"Coupling"to underset"n-Butane"(CH_3CH_2CH_2CH_3)` `CH_3oversetCH_2+CH_2oversetCH_3 overset"Disproportionation"to underset"Ethane"(CH_3-CH_3)+underset"Ethene"(CH_2=CH_2)`