Why Does Electrophilic Hydration Work?
An alkene placed in an aqueous non-nucleophilic strong acid immediately “reaches out” with its double bond and attacks one of the acid’s hydrogens in red (while the bond between the oxygen and hydrogen performs heterolytic cleavage towards the oxygen- in other words, both electrons that were in the oxygen/hydrogen single bond move onto the oxygen). A carbocation is formed on the original alkene (now alkane) in the more substituted position where the oxygen end of water will attack with its 4 non-bonded valence electrons (it has 6 total valence electrons because it is found in group 6 on the periodic table and the second row down- 2 in a 2S orbital and 4 in 2P orbitals. For each bond oxygen has made, oxygen has donated 1 valence electron to that bond. This leaves oxygen with 4 non-bonded valence electrons). After the blue oxygen forms its 3rd bond with the more substituted carbon, it develops a positive charge (3 bonds and 2 valence electrons make the blue oxygen have a formal charge of
