Using anhydrous $\mathrm{AlCl}_3$ as catalyst, which one of the following reactions produces ethylbenzene…

Using anhydrous $\mathrm{AlCl}_3$ as catalyst, which one of the following reactions produces ethylbenzene $(\mathrm{PhEt})$ ?
  1. $\mathrm{H}_3 \mathrm{C}-\mathrm{CH}_2 \mathrm{OH}+\mathrm{C}_6 \mathrm{H}_6$
  2. $\mathrm{CH}_3-\mathrm{CH}=\mathrm{CH}_2+\mathrm{C}_6 \mathrm{H}_6$
  3. $\mathrm{H}_2 \mathrm{C}=\mathrm{CH}_2+\mathrm{C}_6 \mathrm{H}_6$
  4. $\mathrm{H}_3 \mathrm{C}-\mathrm{CH}_3+\mathrm{C}_6 \mathrm{H}_6$

Solution

In Friedel craft reaction benzene with ethylene in presence of $\mathrm{HCl}$ and anhydrous $\mathrm{AlCl}_3$ reacts to form ethyl benzene. Related Theory Anhydrous $\mathrm{AlCl}_3$ is used as a catalyst because it acts as a Lewis acid which can accept electron by forming intermediates and also by speeding up the reaction. It also leads in the creation of carbocation which is used in the electrophilic substitution reaction.

Asked in: NEET 2004

Practice more Hydrocarbons questions on Aicharya