What happens when:
(i) Ethyl alcohol is heated in the presence of Al2O3 at 493 K?
(ii) Ethylene dibromide is heated with zinc dust?
(i) Ethylene is formed.
(ii) Ethylene is formed by dehalogenation reaction.
Discuss the mechanism of addition hydrogen acids to symmetrical alkenes. Justify the order of reactivity of halogen acids HI > HBr > HCl.