1.1. Ethylbenzene, C₆H₅CH₂CH₃, is an important chemical intermediate in the manufacture of polystyrene, pesticides, rubber, paint and inks.

The synthesis of ethylbenzene can occur via Friedel-Crafts alkylation using ethene, hydrogen chloride, benzene and an aluminium chloride, AlCl₃, catalyst.

Name the mechanism for the reaction of ethene and hydrogen chloride.

Write an equation for the subsequent formation of the carbocation that reacts with benzene to produce ethylbenzene.

1.2. Outline the mechanism for the reaction of benzene with the carbocation that was formed in part (a).

1.3. Ethylbenzene can also be formed by reacting ethanoyl chloride with benzene, in the presence of an AlCl₃ catalyst.

Outline the mechanism for the reaction of the ethanoyl chloride with the catalyst to form the acylium ion needed for electrophilic substitution.

1.4. Aluminium chloride is used as the catalyst in the reaction between benzene and ethanoyl chloride.

Explain how the catalyst reforms.