Organic chemistry determing nucleophile strength

[physstudent1]

this isn't exactly an specific question but a general one. I know that weak bases make good nucleophiles but how do I determine what bases are the weakest, what is weak enough to be considered a "good nucleophile" I'm a little confused please help thanks a lot!

 

[GCT]

this isn't exactly an specific question but a general one. I know that weak bases make good nucleophiles but how do I determine what bases are the weakest, what is weak enough to be considered a "good nucleophile" I'm a little confused please help thanks a lot!

In general the more basic an agent is the more nucleophilic , however there are other factors to consider besides basicity. Your teacher is probably not going to get specific , just know the common bases that are considered weak or strong.

 

[STLCards002]

To determine base strength you need to look at the pKa value for the molecules conjugate acid (add an H+ to the molecule). If the conjugate acid has a low pKa (strong acid) then the original molecule is a weak base...and high pKa=strong base.