Alkenes undergo Electrophillic Addition Reactions. Electrophiles are added across double bond. In given reaction the H⁺ is first added across double bond as the double bond being denser in electron density act as a neucleophile. A carbocation formed depends upon the nature of Alkene, if alkene is symmetrical (as in our case) then positive charge can get any position, but in case of unsymmetrical alkene the positive charge will go to that carbon which is attached to more carbon atoms. Then the water molecule attacks the carbocation and forms alcohol.
