Electrophilic addition happens when an electron-rich substance (like an alkene with a carbon-carbon double bond) gets attacked by an electrophile (electron-loving species).

Think of this like a magnet! The alkene is like a super-attractive magnet that lures the electrophile into attacking it.

• Example: Ethene (C2H4) + Bromine Water (Br2)

• Here's what happens

  Imagine two dance partners (the two bromine atoms). One gets attracted and joins the dance floor (alkene), leaving the other alone. The lonely partner (bromine ion) then finds a new partner (the carbocation) to dance with!

  • The bromine molecule gets close to the double bond and feels a bit uneasy (or polarized). This makes one bromine atom a bit positive.
  • The positive bromine gets attracted to the alkene's double bond and goes for it!
  • This results in a break-up: one bromine gets attached, while the other is left with a negative charge. This also creates a carbocation (a positively charged carbon).
  • The lonely negative bromine ion then joins the carbocation, forming 1,2-dibromoethane.

• Example: But-2-ene (C4H8) + Hydrogen Bromide (HBr)

• Steps

  Imagine this as a trio. The bromine doesn't want the third wheel (hydrogen) anymore. But the hydrogen finds a new friend (carbocation), and bromine is back in the game by rejoining them.

  • The hydrogen, being a little positive (thanks to the bromine), gets attracted to the alkene's double bond.
  • The hydrogen attaches itself, leaving behind a carbocation and a bromide ion.
  • The bromide ion teams up with the carbocation, forming 2-bromobutane.