Chemistry LC Question

checkcheek

Hi guys!!

You know when u have the bromination(Br2) of ethene!

And when you react it with sodiom chloride solution u get those other products!


Will the product still be the same if u use HCl or CL2 instead of BR2


If any gets what im saying!! But i think im making it sound more confusing

SuchGold

1-bromo-2-chloroethane is formed when the carbonium ion is attacked by the Cl- ion and 2-bromoethanol is formed when the carbonium ion is attacked by a water molecule.

The carbonium ion will form when HCl, Br2 or Cl2 react with ethene.
So yes it would be the same, because its the carbonium ion that's involved in the reaction. This is evidence for the existence of the carbonium ion.

partyatmygaff

I've drawn up a simple reaction mechanism for the halogenation (Bromination in this case) of an alkene. The carbonium ion will form with most halogens but only Bromine and larger halogens are big enough to support a cyclical structure.


For those unfamiliar with reaction schemes like these, curly arrows represent electron movement. Straight arrows represent progression through the scheme.

Essentially with Bromine/Chlorine and a simple alkene such ethene you've got a symmetrical reagent being added to a symmetrical double bound which leads to the products being fairly predictable.

Realistically for the LC, you won't be asked anything more than bromination of ethene. If you get asked for the products of a bromine addition you have them in that scheme. If you get asked to add Cl2, your products will be the exact same except there will be no cyclical intermediate (And obviously you'd have to replace all the Br atoms with Cl atoms in that scheme!).