Q12 / 160 · AP EAMCET 2012 · Chemistry
The chlorination of ethane is an example for which type of the following reactions?
- ANucleophilic substitution
- Correct answerBElectrophilic substitution
- CFree radical substitution
- DRearrangement
Solution
Chlorination of ethane takes place by free radical substitution and involves the following steps
Step I Initiation step
$\mathrm{Cl}_2 \stackrel{h v}{\longrightarrow} 2 \mathrm{Cl}^{\bullet}$
Step II Propagation step
Step III Termination step $\begin{aligned} \mathrm{CH}_3 \mathrm{CH}_2^*+\mathrm{Cl}^{\bullet} & \longrightarrow \mathrm{CH}_3 \mathrm{CH}_2 \mathrm{Cl} \\ \mathrm{Cl}^*+\mathrm{Cl}^* & \longrightarrow \mathrm{Cl}_2 \\ 2 \mathrm{CH}_3 \mathrm{CH}_2^* & \longrightarrow \mathrm{CH}_3 \mathrm{CH}_2 \mathrm{CH}_2 \mathrm{CH}_3\end{aligned}$
Step III Termination step $\begin{aligned} \mathrm{CH}_3 \mathrm{CH}_2^*+\mathrm{Cl}^{\bullet} & \longrightarrow \mathrm{CH}_3 \mathrm{CH}_2 \mathrm{Cl} \\ \mathrm{Cl}^*+\mathrm{Cl}^* & \longrightarrow \mathrm{Cl}_2 \\ 2 \mathrm{CH}_3 \mathrm{CH}_2^* & \longrightarrow \mathrm{CH}_3 \mathrm{CH}_2 \mathrm{CH}_2 \mathrm{CH}_3\end{aligned}$
Hence, the correct answer is option: 'B'.