Write a chemical equation to show the preparation of ethene from dehydration of an alcohol and dehydrohalogenation of alkyl halides:

Dehydration of Alcohol:
C₂H₅OH → C₂H₄ + H₂O (In the presence of concentrated H₂SO₄)

Dehydrohalogenation of Alkyl Halide:
C₂H₅Cl → C₂H₄ + HCl (In the presence of alcoholic KOH)