Question

Explain the preparation of ethene gas by dehydration, giving chemical equations.

Answer 1

Ethane when heated in the presence of conc. $H_{2}S{O}_4$ or $H_{3}P{O}_4$ at $443$K temperature results in the formation of ethane. As a molecule of water is removed during the reaction, this reaction is known as the dehydration of alcohol.
$\underset{Ethanol}{C{H}_{3}C{H}_{2}OH}\stackrel{443K}{\underset{\left[H_{3}P{O}_4\right]}{\underset{OR}{\underset{\left[H_{2}S{O}_4\right]}{\to }}}}\underset{Ethene}{C{H}_2=C{H}_2}+H_{2}O$