In this mechanism, we begin with a double bond acting as a nucleophile, seeking an electrophile, which in this case is sulfuric acid (H₂SO₄). It’s crucial to visualize sulfuric acid correctly, as the hydrogen (H) is attached to an oxygen (O), not sulfur (S). This understanding aids in the deprotonation process, where the double bond captures a proton (H⁺) from sulfuric acid, resulting in the formation of a carbocation.

The stability of the carbocation is essential; initially, it is secondary, but through a methyl shift, it can become tertiary, enhancing its stability. This shift involves moving a methyl group from an adjacent carbon to the positively charged carbon, creating a new carbocation with the positive charge now located on a more stable tertiary carbon.

Next, we consider the nucleophiles available to attack the carbocation. Although the conjugate base of sulfuric acid (OSO₃H^-) is a stronger nucleophile due to its negative charge, the abundance of water molecules in the solution means that water is more likely to collide with and attack the carbocation. This highlights the importance of concentration in determining which nucleophile will react.

Upon the attack by water, a new product forms, which includes an alcohol and a positively charged oxygen (O⁺) due to the formation of three bonds. The final step in this acid-catalyzed mechanism is deprotonation, where the negatively charged conjugate base (OSO₃H^-) removes a proton from the oxygen, regenerating sulfuric acid and yielding the final product: an alcohol.

This reaction exemplifies the Markovnikov rule, where the more substituted carbon receives the hydroxyl group, and it is important to note that the sulfuric acid acts as a catalyst, remaining unchanged throughout the reaction. Understanding this mechanism is vital for mastering reactions involving alkenes and acids, and practicing it will solidify your grasp of the concepts involved.