S_N2         S_N1

1. kinetic order?

2. influence of nucleophile
   concn on reaction rate?

3. stereochemistry of rxn
   (inversion, racemization,
   partial racemization)?

4. # of steps in overall
   rxn mechanism?

5. best solvent for rxn
   (nonpolar, polar aprotic,
   polar protic)?

6. most reactive R in R-X?
   CH₃, 1^o, 2^o, 3^o ?

7. influence of nucleophile
   nucleophilicity on rxn
   rate?

8. key intermediate is a
   carbocation?

9. key transition. state has
   "penta-coordinate" C atom?
 

                                        hlammon - 11/9/98