During the dehydration of alcohols to alkenes by heating with conc.H₂SO₄, the initiation step is

protonation of an alcohol molecule

The correct answer is option 2. protonation of alcohol molecule

During the dehydration of alcohols to form alkenes, the initiation step involves the protonation of the alcohol molecule by a strong acid such as concentrated sulfuric acid \((H_2SO_4)\). The sulfuric acid donates a proton \((H^+)\) to the oxygen atom of the alcohol, forming an oxonium ion or alkyl oxonium ion.

Let us consider an example to understand the mechanism: