The complete mechanism takes place in three steps as shown below :-
Step 1 :- Step 1 involves the release of Hydronium ion (proton) and then the attack of proton on the lone pair electrons of oxygen. By this way protonated alcohol is formed.
Step 2 :- This step is slow and rate determining step. In this step the oxygen with positive charge breaks the bond and leaves it by taking the shared pair of electrons. This leads to the formation of carbocation.
Step 3 :- In this step the Hydronium ions is released by the carbon and the shared electrons are used for the formation of double bond between the two carbon atoms.