Question

Write the mechanism of hydration of ethene to yield ethanol.

Answer 1

Step 1: Protonation of the alkene to form a carbocation by the electrophilic attack of H₃O⁺.

\[\ce{H2O + H+ -> H3O+}\]

Step 2: Nucleophilic attack of water on carbocation.

Step 3: Deprotonation to form an alcohol.

Answer 2

The acid-catalysed hydration of ethene may be represented as:

The mechanism followed by the above reaction may be depicted as:

Step 1: Generation of carbocation: Protonation of ethene yields a carbocation as,

Step 2: Nucleophilic attack of water on carbocation: The carbocation polarises the lone pair electrons of O of water, and hydration takes place.

Step 3: Formation of product, regeneration of the proton: