Question

Name the compound formed when ethanol is heated at 443 K in the presence of conc. \[\ce{H2SO4}\] and draw its electron dot structure.

State the role of conc. \[\ce{H2SO4}\] in the reaction.

Answer 1

Ethene is created when 443K ethanol is heated with excess concentrated sulphuric acid.
The mechanism of acid dehydration of ethanol to yield ethene is:

1. 1. The first step is to protonate the oxygen atom of the -OH group.
   2. The second step is the loss of a water molecule to generate carbonium ions.
   3. Deprotonation, the final step, creates a carbon-carbon double bond.

\[\ce{\underset{Ethanol}{2CH3CH2OH}->[\Delta][Conc.sulphuric acid] \underset{Ethene}{2CH2 = CH2} + \underset{Water}{2H2O}}\]

Sulphuric acid in concentrated form has a dehydrating effect. In light of this, ethanol is produced at 433 K with extra cone. To create ethene, \[\ce{H2SO4}\] undergoes a dehydration process.