ANSWERS: 2
  • They don't... To have a good leaving group you much look at the pKa of the protonated form. For bases this is usually a very high number as they want to be protonated. Good leaving groups include Cl- (pKa of HCl = -7) or ROO- (pKa of ROOH = 5). Both strong acids.
  • First of all weak bases do make good leaving groups....DeanWinfield you might want to do a little more research before posting because the examples that you gave "CL- and ROO-" are actually bases (conjugate bases to be exact), "HCL and ROOH" are the acids. If you have a strong acid, you have a WEAK conjugate BASE. So the originial poster was correct in saying that weak bases make good leaving groups. The reason why is because we want a leaving group that is stable enough to be able to fend for itself once it separates from the originial molecule. Therefore, the more stable the LG after it has left, the "better" the leaving group is. It is because the weak base has the ability to hold on to extra electrons more easily and is also less likey to be protonated that it is the best leaving group.

Copyright 2023, Wired Ivy, LLC

Answerbag | Terms of Service | Privacy Policy