Acid-catalysed hydration of an alkene Mechanism: Steps and Conditions

Conditions

Dilute H₂SO₄ in water, or H₃PO₄ and steam (industrial).

Red curly arrows show where each pair of electrons moves.

Step 1The π bond takes a proton from H₃O⁺, forming a tertiary carbocation.

Step 2Water attacks the carbocation.

Step 3Another water removes the proton, giving the alcohol and regenerating H₃O⁺.

The π electrons of a C=C are exposed and electron-rich, so alkenes react with electrophiles. The two new groups add across the double bond.

Practise this mechanismDraw the curly arrows yourself and Bondline checks each one. Or add it to your notes and watch it in 3D.